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• Entry lvl. COBOL Control Breaks

  - by Kyle Benzle

  I'm working in COBOL with a double control break to print a hospital record. The input is one record per line, with, hospital info first, then patient info. There are multiple records per hospital, and multiple services per patient. The idea is, using a double control break, to print one hospital name, then all the patients from that hospital. Then print the patient name just once for all services, like the below. I'm having trouble with my output, and am hoping someone can help me get it in order. I am using AccuCobol to compile experts-exchange does not allow .cob and .dat so the extentions were changed to .txt The files are: the .cob lab5b.cob the input / output: lab5bin.dat, lab5bout.dat The assignment: http://www.cse.ohio-state.edu/~sgomori/314/lab5.html Hospital Number: 001 Hospital Name: Mount Carmel 00001 Griese, Brian Ear Infection 08/24/1999 300.00 Diaper Rash 09/05/1999 25.00 Frontal Labotomy 09/25/1999 25,000.00 Rear Labotomy 09/26/1999 25,000.00 Central Labotomy 09/28/1999 24,999.99 The total amount owed for this patient is: $.......... (End of Hospital) The total amount owed for this hospital is: $......... enter code here IDENTIFICATION DIVISION. PROGRAM-ID. LAB5B. ENVIRONMENT DIVISION. INPUT-OUTPUT SECTION. FILE-CONTROL. SELECT FILE-IN ASSIGN TO 'lab5bin.dat' ORGANIZATION IS LINE SEQUENTIAL. SELECT FILE-OUT ASSIGN TO 'lab5bout.dat' ORGANIZATION IS LINE SEQUENTIAL. DATA DIVISION. FILE SECTION. FD FILE-IN. 01 HOSPITAL-RECORD-IN. 05 HOSPITAL-NUMBER-IN PIC 999. 05 HOSPITAL-NAME-IN PIC X(20). 05 PATIENT-NUMBER-IN PIC 99999. 05 PATIENT-NAME-IN PIC X(20). 05 SERVICE-IN PIC X(30). 05 DATE-IN PIC 9(8). 05 OWED-IN PIC 9(7)V99. FD FILE-OUT. 01 REPORT-REC-OUT PIC X(100). WORKING-STORAGE SECTION. 01 WS-WORK-AREAS. 05 WS-HOLD-HOSPITAL-NUM PIC 999 VALUE ZEROS. 05 WS-HOLD-PATIENT-NUM PIC 99999 VALUE ZEROS. 05 ARE-THERE-MORE-RECORDS PIC XXX VALUE 'YES'. 88 MORE-RECORDS VALUE 'YES'. 88 NO-MORE-RECORDS VALUE 'NO '. 05 FIRST-RECORD PIC XXX VALUE 'YES'. 05 WS-PATIENT-TOTAL PIC 9(9)V99 VALUE ZEROS. 05 WS-HOSPITAL-TOTAL PIC 9(9)V99 VALUE ZEROS. 05 WS-PAGE-CTR PIC 99 VALUE ZEROS. 01 WS-DATE. 05 WS-YR PIC 9999. 05 WS-MO PIC 99. 05 WS-DAY PIC 99. 01 HL-HEADING1. 05 PIC X(49) VALUE SPACES. 05 PIC X(14) VALUE 'OHIO INSURANCE'. 05 PIC X(7) VALUE SPACES. 05 HL-PAGE PIC Z9. 05 PIC X(14) VALUE SPACES. 05 HL-DATE. 10 HL-MO PIC 99. 10 PIC X VALUE '/'. 10 HL-DAY PIC 99. 10 PIC X VALUE '/'. 10 HL-YR PIC X VALUE '/'. 01 HL-HEADING2. 05 PIC XXXXXXXXXX VALUE 'HOSPITAL: '. 05 HL-HOSPITAL PIC 999. 01 HL-HEADING3. 05 PIC X(7) VALUE "Patient". 05 PIC X(3) VALUE SPACES. 05 PIC X(7) VALUE "Patient". 05 PIC X(39) VALUE SPACES. 05 PIC X(7) VALUE "Date of". 05 PIC X(3) VALUE SPACES. 05 PIC X(6) VALUE "Amount". 01 HL-HEADING4. 05 PIC X(6) VALUE "Number". 05 PIC X(4) VALUE SPACES. 05 PIC X(4) VALUE "Name". 05 PIC X(18) VALUE SPACES. 05 PIC X(10) VALUE "Service". 05 PIC X(14) VALUE SPACES. 05 PIC X(8) VALUE "Service". 05 PIC X(2) VALUE SPACES. 05 PIC X(5) VALUE "Owed". 01 DL-PATIENT-LINE. 05 PIC X(28) VALUE SPACES. 05 DL-PATIENT-NUMBER PIC XXXXX. 05 PIC X(21) VALUE SPACES. 05 DL-PATIENT-TOTAL PIC $$$,$$$,$$9.99. 01 DL-HOSPITAL-LINE. 05 PIC X(47) VALUE SPACES. 05 PIC X(16) VALUE 'HOSPITAL TOTAL: '. 05 DL-HOSPITAL-TOTAL PIC $$$,$$$,$$9.99. PROCEDURE DIVISION. 100-MAIN-MODULE. PERFORM 600-INITIALIZATION-RTN PERFORM UNTIL NO-MORE-RECORDS READ FILE-IN AT END MOVE 'NO ' TO ARE-THERE-MORE-RECORDS NOT AT END PERFORM 200-DETAIL-RTN END-READ END-PERFORM PERFORM 400-HOSPITAL-BREAK PERFORM 700-END-OF-JOB-RTN STOP RUN. 200-DETAIL-RTN. EVALUATE TRUE WHEN FIRST-RECORD = 'YES' MOVE PATIENT-NUMBER-IN TO WS-HOLD-PATIENT-NUM MOVE HOSPITAL-NUMBER-IN TO WS-HOLD-HOSPITAL-NUM PERFORM 500-HEADING-RTN MOVE 'NO ' TO FIRST-RECORD WHEN HOSPITAL-NUMBER-IN NOT = WS-HOLD-HOSPITAL-NUM PERFORM 400-HOSPITAL-BREAK WHEN PATIENT-NUMBER-IN NOT = WS-HOLD-PATIENT-NUM PERFORM 300-PATIENT-BREAK END-EVALUATE ADD OWED-IN TO WS-PATIENT-TOTAL. 300-PATIENT-BREAK. MOVE WS-PATIENT-TOTAL TO DL-PATIENT-TOTAL MOVE WS-HOLD-PATIENT-NUM TO DL-PATIENT-NUMBER WRITE REPORT-REC-OUT FROM DL-PATIENT-LINE AFTER ADVANCING 2 LINES ADD WS-PATIENT-TOTAL TO WS-HOSPITAL-TOTAL IF MORE-RECORDS MOVE ZEROS TO WS-PATIENT-TOTAL MOVE PATIENT-NUMBER-IN TO WS-HOLD-PATIENT-NUM END-IF. 400-HOSPITAL-BREAK. PERFORM 300-PATIENT-BREAK MOVE WS-HOSPITAL-TOTAL TO DL-HOSPITAL-TOTAL WRITE REPORT-REC-OUT FROM DL-HOSPITAL-LINE AFTER ADVANCING 2 LINES IF MORE-RECORDS MOVE ZEROS TO WS-HOSPITAL-TOTAL MOVE HOSPITAL-NUMBER-IN TO WS-HOLD-HOSPITAL-NUM PERFORM 500-HEADING-RTN END-IF. 500-HEADING-RTN. ADD 1 TO WS-PAGE-CTR MOVE WS-PAGE-CTR TO HL-PAGE MOVE WS-HOLD-HOSPITAL-NUM TO HL-HOSPITAL WRITE REPORT-REC-OUT FROM HL-HEADING1 AFTER ADVANCING PAGE WRITE REPORT-REC-OUT FROM HL-HEADING2 AFTER ADVANCING 2 LINES. WRITE REPORT-REC-OUT FROM HL-HEADING3 AFTER ADVANCING 2 LINES. 600-INITIALIZATION-RTN. OPEN INPUT FILE-IN OUTPUT FILE-OUT *159 ACCEPT WS-DATE FROM DATE YYYYMMDD MOVE WS-YR TO HL-YR MOVE WS-MO TO HL-MO MOVE WS-DAY TO HL-DAY. 700-END-OF-JOB-RTN. CLOSE FILE-IN FILE-OUT.

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• Trouble passing a template function as an argument to another function in C++

  - by Darel

  Source of the problem -Accelerated C++, problem 8-5 I've written a small program that examines lines of string input, and tallies the number of times a word appears on a given line. The following code accomplishes this: #include <map> #include <iostream> #include <string> #include <vector> #include <list> #include <cctype> #include <iterator> using std::vector; using std::string; using std::cin; using std::cout; using std::endl; using std::getline; using std::istream; using std::string; using std::list; using std::map; using std::isspace; using std::ostream_iterator; using std::allocator; inline void keep_window_open() { cin.clear(); cout << "Please enter EOF to exit\n"; char ch; cin >> ch; return; } template <class Out> void split(const string& s, Out os) { vector<string> ret; typedef string::size_type string_size; string_size i = 0; // invariant: we have processed characters `['original value of `i', `i)' while (i != s.size()) { // ignore leading blanks // invariant: characters in range `['original `i', current `i)' are all spaces while (i != s.size() && isspace(s[i])) ++i; // find end of next word string_size j = i; // invariant: none of the characters in range `['original `j', current `j)' is a space while (j != s.size() && !isspace(s[j])) ++j; // if we found some nonwhitespace characters if (i != j) { // copy from `s' starting at `i' and taking `j' `\-' `i' chars *os++ = (s.substr(i, j - i)); i = j; } } } // find all the lines that refer to each word in the input map<string, vector<int> > xref(istream& in) // works // now try to pass the template function as an argument to function - what do i put for templated type? //map<string, vector<int> > xref(istream& in, void find_words(vector<string, typedef Out) = split) #LINE 1# { string line; int line_number = 0; map<string, vector<int> > ret; // read the next line while (getline(in, line)) { ++line_number; // break the input line into words vector<string> words; // works // #LINE 2# split(line, back_inserter(words)); // #LINE 3# //find_words(line, back_inserter(words)); // #LINE 4# attempting to use find_words as an argument to function // remember that each word occurs on the current line for (vector<string>::const_iterator it = words.begin(); it != words.end(); ++it) ret[*it].push_back(line_number); } return ret; } int main() { cout << endl << "Enter lines of text, followed by EOF (^Z):" << endl; // call `xref' using `split' by default map<string, vector<int> > ret = xref(cin); // write the results for (map<string, vector<int> >::const_iterator it = ret.begin(); it != ret.end(); ++it) { // write the word cout << it->first << " occurs on line(s): "; // followed by one or more line numbers vector<int>::const_iterator line_it = it->second.begin(); cout << *line_it; // write the first line number ++line_it; // write the rest of the line numbers, if any while (line_it != it->second.end()) { cout << ", " << *line_it; ++line_it; } // write a new line to separate each word from the next cout << endl; } keep_window_open(); return 0; } As you can see, the split function is a template function to handle various types of output iterators as desired. My problem comes when I try to generalize the xref function by passing in the templated split function as an argument. I can't seem to get the type correct. So my question is, can you pass a template function to another function as an argument, and if so, do you have to declare all types before passing it? Or can the compiler infer the types from the way the templated function is used in the body? To demonstrate the errors I get, comment out the existing xref function header, and uncomment the alternate header I'm trying to get working (just below the following commment line.) Also comment the lines tagged LINE 2 and LINE 3 and uncomment LINE 4, which is attempting to use the argument find_words (which defaults to split.) Thanks for any feedback!

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• Session Report: What’s New in JSF: A Complete Tour of JSF 2.2

  - by Janice J. Heiss

  On Wednesday, Ed Burns, Consulting Staff Member at Oracle, presented a session, CON3870 -- “What’s New in JSF: A Complete Tour of JSF 2.2,” in which he provided an update on recent developments in JavaServer Faces 2.2. He began by emphasizing that, “JavaServer Faces 2.2 continues the evolution of the Java EE standard user interface technology. Like previous releases, this iteration is very community-driven and transparent.” He pointed out that since JSF was introduced at the 2001 JavaOne Keynote, it has had a long and successful run and has found a home in applications where the UI logic resides entirely on the server where the model and UI logic is. In such cases, the browser performs fairly simple functions. However, developers can take advantage of the power of browsers, something that Project Avatar is focused on by letting developers author their applications so the UI logic is running on the client and communicating to the back end via RESTful web services. “Most importantly,” remarked Burns, “JSF 2.2 offers a really good migration path because even in the scope of one application you could have an app written with JSF that has its UI logic on the server and, on a gradual basis, you could migrate parts of the app over to use client-side technologies. This can be done at any level of granularity – per page or per collection of pages. It all depends on what you want to do.” His presentation, which focused on the basic new features of JSF 2.2, began by restating the scope of JSF and encouraged attendees to check out Roger Kitain’s session: CON5133 “Techniques for Responsive Real-Time Web UIs.” Burns explained that JSF has endured because, “We still need web apps that are maintainable, localizable, quick to build, accessible, secure, look great and are fun to use.” It is used on every continent – the curious can go here to check out where its unofficial usage is tracked. He emphasized the significance of the UI logic being substantially on the server. This: Separates Component Semantics from Rendering, Allows components to “own” their little patch of the UI -- encode/decode, And offers a well-defined lifecycle: Inversion of Control. Burns reminded attendees that JSR-344, the spec for JSF 2.2, is now on Java Community Process 2.8, a revised version of the JCP that allows for more openness and transparency. He then offered some tools for community access to JSF 2.2:    * Public java.net projects spec http://jsf-spec.java.net/ impl http://jsf.java.net/ Open Source: GPL+Classpath Exception    * Mailing Lists [email protected]                                Public readable archive, JSPA signed member read/write [email protected]                                     Public readable archive, any java.net member read/write                         All mail sent to jsr344-experts is sent to users. * Issue Tracker spec http://jsf-spec.java.net/issues/ impl http://jsf.java.net/issues/ JSF 2.2, which is JSR 344, has a Public Review Draft planned by December 2012 with no need for a Renewal Ballot. The Early Draft Review of JSR 344 was published on December 8, 2011. Interested developers are encouraged to offer their input. Six Big Ticket Features of JSF 2.2 Burns summarized the six big ticket features of JSF 2.2:* HTML5 Friendly Markup Support Pass through attributes and elements * Faces Flows* Cross Site Request Forgery Protection* Loading Facelets via ResourceHandler* File Upload Component* Multi-Templating He explained that he called it “HTML 5 friendly” because there is really nothing HTML 5 specific about it -- it could be 4. But it enables developers to use new elements that are present in HTML5 without having a JSF component library that is written to take advantage of those specifically. It gives the page author the ability to use plain HTML5 to write their page, but to still take advantage of the server-side available in JSF. He presented a demo showing JSF 2.2’s ability to leverage the expressiveness of HTML5. Burns then explained the significance of face flows, which offer function points and quantify how much work has taken place, something of great value to JSF users. He went on to talk about JSF 2.2.’s cross-site request forgery protection (CSRF) and offered details about how it protects applications against attack. Then he talked about JSF 2.2’s File Upload Component and explained that the final specification will have Ajax and non-Ajax support. The current milestone has non-Ajax support implemented. He then went on to explain its capacity to add facelets through ResourceHandler. Previously, JSF 2.0 added Facelets and ResourceHandler as disparate units; now in JSF 2.2 the two concepts are unified. Finally, he explained the concept of multi-templating in JSF 2.2 and went on to discuss more medium-level features of the release. For an easy, low maintenance way of staying in touch with JSF developments go to JSF’s Twitter page where every month or so, important updates are offered.

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• SQL SERVER – PAGEIOLATCH_DT, PAGEIOLATCH_EX, PAGEIOLATCH_KP, PAGEIOLATCH_SH, PAGEIOLATCH_UP – Wait Type – Day 9 of 28

  - by pinaldave

  It is very easy to say that you replace your hardware as that is not up to the mark. In reality, it is very difficult to implement. It is really hard to convince an infrastructure team to change any hardware because they are not performing at their best. I had a nightmare related to this issue in a deal with an infrastructure team as I suggested that they replace their faulty hardware. This is because they were initially not accepting the fact that it is the fault of their hardware. But it is really easy to say “Trust me, I am correct”, while it is equally important that you put some logical reasoning along with this statement. PAGEIOLATCH_XX is such a kind of those wait stats that we would directly like to blame on the underlying subsystem. Of course, most of the time, it is correct – the underlying subsystem is usually the problem. From Book On-Line: PAGEIOLATCH_DT Occurs when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Destroy mode. Long waits may indicate problems with the disk subsystem. PAGEIOLATCH_EX Occurs when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Exclusive mode. Long waits may indicate problems with the disk subsystem. PAGEIOLATCH_KP Occurs when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Keep mode. Long waits may indicate problems with the disk subsystem. PAGEIOLATCH_SH Occurs when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Shared mode. Long waits may indicate problems with the disk subsystem. PAGEIOLATCH_UP Occurs when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Update mode. Long waits may indicate problems with the disk subsystem. PAGEIOLATCH_XX Explanation: Simply put, this particular wait type occurs when any of the tasks is waiting for data from the disk to move to the buffer cache. ReducingPAGEIOLATCH_XX wait: Just like any other wait type, this is again a very challenging and interesting subject to resolve. Here are a few things you can experiment on: Improve your IO subsystem speed (read the first paragraph of this article, if you have not read it, I repeat that it is easy to say a step like this than to actually implement or do it). This type of wait stats can also happen due to memory pressure or any other memory issues. Putting aside the issue of a faulty IO subsystem, this wait type warrants proper analysis of the memory counters. If due to any reasons, the memory is not optimal and unable to receive the IO data. This situation can create this kind of wait type. Proper placing of files is very important. We should check file system for the proper placement of files – LDF and MDF on separate drive, TempDB on separate drive, hot spot tables on separate filegroup (and on separate disk), etc. Check the File Statistics and see if there is higher IO Read and IO Write Stall SQL SERVER – Get File Statistics Using fn_virtualfilestats. It is very possible that there are no proper indexes on the system and there are lots of table scans and heap scans. Creating proper index can reduce the IO bandwidth considerably. If SQL Server can use appropriate cover index instead of clustered index, it can significantly reduce lots of CPU, Memory and IO (considering cover index has much lesser columns than cluster table and all other it depends conditions). You can refer to the two articles’ links below previously written by me that talk about how to optimize indexes. Create Missing Indexes Drop Unused Indexes Updating statistics can help the Query Optimizer to render optimal plan, which can only be either directly or indirectly. I have seen that updating statistics with full scan (again, if your database is huge and you cannot do this – never mind!) can provide optimal information to SQL Server optimizer leading to efficient plan. Checking Memory Related Perfmon Counters SQLServer: Memory Manager\Memory Grants Pending (Consistent higher value than 0-2) SQLServer: Memory Manager\Memory Grants Outstanding (Consistent higher value, Benchmark) SQLServer: Buffer Manager\Buffer Hit Cache Ratio (Higher is better, greater than 90% for usually smooth running system) SQLServer: Buffer Manager\Page Life Expectancy (Consistent lower value than 300 seconds) Memory: Available Mbytes (Information only) Memory: Page Faults/sec (Benchmark only) Memory: Pages/sec (Benchmark only) Checking Disk Related Perfmon Counters Average Disk sec/Read (Consistent higher value than 4-8 millisecond is not good) Average Disk sec/Write (Consistent higher value than 4-8 millisecond is not good) Average Disk Read/Write Queue Length (Consistent higher value than benchmark is not good) Note: The information presented here is from my experience and there is no way that I claim it to be accurate. I suggest reading Book OnLine for further clarification. All of the discussions of Wait Stats in this blog is generic and varies from system to system. It is recommended that you test this on a development server before implementing it to a production server. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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• Surface development: it&rsquo;s just like software development

  - by Dennis Vroegop

  Surface is magic. Everyone using it seems to think that way. And I have to be honest, after working for almost 2 years with the platform I still get that special feeling the moment I turn on the unit to do some more work. The whole user experience, the rich environment of the SDK, the touch, even the look and feel of the Surface environment is so much different from the stuff I’ve been working on all my career that I am still bewildered by it. But… and this is a big but.. in the end we’re still talking about a computer and that needs software to become useful. Deep down the magic of the Surface unit there is a PC somewhere, running Windows Vista and the .net framework 3.5. When you write that magic software that makes the platform come alive you’re still working with .net, WPF/XNA, C#, VB.Net and all those other tools and technologies you know so well. Sure, the whole user experience is different from what you’ve known. And the way of thinking about users, their interaction and the positioning of screen elements requires a whole new paradigm. And that takes time. It took me about half a year before I had the feeling I got it nailed down. But when that moment came (about 18 months ago…) I realized that everything I had learned so far on software development still is true when it comes to Surface. The last 6 months I have been working with some people with a different background to start a new company. The idea was that the new company would be focussing on Surface and Surface only. These people come from a marketing background and had some good ideas for some applications. And I have to admit: their ideas were good. Very good. Where it all fell down of course is that these ideas need to be implemented in a piece of software. And creating great software takes skilled developers and a lot of time and money. That’s where things went wrong: the marketing guys didn’t realize and didn’t want to realize that software development is a job that takes skill. You can’t just hire a bunch of developers and expect them to deliver the best sort of software, especially not when it comes to Surface. I tried to explain that yes, their User Interface in Photoshop looked great, but no: I couldn’t develop an application like that in a weeks time. Even worse: the while backend of the software (WCF for communications, SQL Server for the database, etc) would take a lot more time than the frontend. They didn’t understand. It took them a couple of days to drawn the UI in Photoshop so in Blend I should be able to build the software in about the same amount of time. Well, you and I know that it doesn’t work that way. Software is hard to write, and even harder to write well, and it takes skill and dedication. It’s not something you can do as fast as you can draw a mock up for a Surface application in Photohop. The same holds true for web applications of course. A lot of designers there fail to appreciate the hard work that goes into writing the plumbing for a good web app that can handle thousands of users. Although the UI is very important, it’s not all there is to it. And in Surface development this is the same. The UI should create the feeling of magic, but the software behind it is what makes it come alive. And that takes time. A lot of time. So brush of you skills and don’t throw them away if you start developing for Surface. Because projects (and colaborations) can fail there as hard as they can in any other area of software development. On a side note: we decided to stop the colaboration (something the other parties involved didn’t appreciate and were very angry about) and decided to hire a designer for the Surface projects. The focus is back where it belongs: on the software development we know so well and have been doing very well for 13 years. UI is just a part of the whole project and not the end product. So my company Detrio is still going strong when it comes to develivering Surface solutions but once again from a technological background, not a marketing background.

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• Your thoughts on Best Practices for Scientific Computing?

  - by John Smith

  A recent paper by Wilson et al (2014) pointed out 24 Best Practices for scientific programming. It's worth to have a look. I would like to hear opinions about these points from experienced programmers in scientific data analysis. Do you think these advices are helpful and practical? Or are they good only in an ideal world? Wilson G, Aruliah DA, Brown CT, Chue Hong NP, Davis M, Guy RT, Haddock SHD, Huff KD, Mitchell IM, Plumbley MD, Waugh B, White EP, Wilson P (2014) Best Practices for Scientific Computing. PLoS Biol 12:e1001745. http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1001745 Box 1. Summary of Best Practices Write programs for people, not computers. (a) A program should not require its readers to hold more than a handful of facts in memory at once. (b) Make names consistent, distinctive, and meaningful. (c) Make code style and formatting consistent. Let the computer do the work. (a) Make the computer repeat tasks. (b) Save recent commands in a file for re-use. (c) Use a build tool to automate workflows. Make incremental changes. (a) Work in small steps with frequent feedback and course correction. (b) Use a version control system. (c) Put everything that has been created manually in version control. Don’t repeat yourself (or others). (a) Every piece of data must have a single authoritative representation in the system. (b) Modularize code rather than copying and pasting. (c) Re-use code instead of rewriting it. Plan for mistakes. (a) Add assertions to programs to check their operation. (b) Use an off-the-shelf unit testing library. (c) Turn bugs into test cases. (d) Use a symbolic debugger. Optimize software only after it works correctly. (a) Use a profiler to identify bottlenecks. (b) Write code in the highest-level language possible. Document design and purpose, not mechanics. (a) Document interfaces and reasons, not implementations. (b) Refactor code in preference to explaining how it works. (c) Embed the documentation for a piece of software in that software. Collaborate. (a) Use pre-merge code reviews. (b) Use pair programming when bringing someone new up to speed and when tackling particularly tricky problems. (c) Use an issue tracking tool. I'm relatively new to serious programming for scientific data analysis. When I tried to write code for pilot analyses of some of my data last year, I encountered tremendous amount of bugs both in my code and data. Bugs and errors had been around me all the time, but this time it was somewhat overwhelming. I managed to crunch the numbers at last, but I thought I couldn't put up with this mess any longer. Some actions must be taken. Without a sophisticated guide like the article above, I started to adopt "defensive style" of programming since then. A book titled "The Art of Readable Code" helped me a lot. I deployed meticulous input validations or assertions for every function, renamed a lot of variables and functions for better readability, and extracted many subroutines as reusable functions. Recently, I introduced Git and SourceTree for version control. At the moment, because my co-workers are much more reluctant about these issues, the collaboration practices (8a,b,c) have not been introduced. Actually, as the authors admitted, because all of these practices take some amount of time and effort to introduce, it may be generally hard to persuade your reluctant collaborators to comply them. I think I'm asking your opinions because I still suffer from many bugs despite all my effort on many of these practices. Bug fix may be, or should be, faster than before, but I couldn't really measure the improvement. Moreover, much of my time has been invested on defence, meaning that I haven't actually done much data analysis (offence) these days. Where is the point I should stop at in terms of productivity? I've already deployed: 1a,b,c, 2a, 3a,b,c, 4b,c, 5a,d, 6a,b, 7a,7b I'm about to have a go at: 5b,c Not yet: 2b,c, 4a, 7c, 8a,b,c (I could not really see the advantage of using GNU make (2c) for my purpose. Could anyone tell me how it helps my work with MATLAB?)

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• Cant correctly install Lazarus

  - by user206316

  I have a little problem with installing and running Lazarus. I just upgrade ubuntu from 13.04 to 13.10. When i had 13.04, i could install lazarus without any problems, but in 13.10 lazarus magicaly dissapeared, and when i tried install it from ubuntu software center, it said something like in my software resources lazarus-ide-0.9.30.4 doesnt exist. After some research on net i tried delete all files from earlier installations, download deb packages from sourceforge and install them, but when i want to instal fpc-src, error shows up with output: (Reading database ... 100% (Reading database ... 239063 files and directories currently installed.) Unpacking fpc-src (from .../Stiahnut/Lazarus/fpc-src.deb) ... dpkg: error processing /home/richi/Stiahnut/Lazarus/fpc-src.deb (--install): trying to overwrite '/usr/share/fpcsrc/2.6.2/rtl/nativent/tthread.inc', which is also in package fpc-source-2.6.2 2.6.2-5 dpkg-deb (subprocess): decompressing archive member: internal gzip write error: Broken pipe dpkg-deb: error: subprocess <decompress> returned error exit status 2 dpkg-deb (subprocess): cannot copy archive member from '/home/richi/Stiahnut/Lazarus/fpc-src.deb' to decompressor pipe: failed to write (Broken pipe) when i started lazarus, it of course tell me that it cant find fpc compier and fpc sources. So, please, i really need program for school and i dont wanna reinstall os anymore or something like that :( (Ubuntu 13.10 64bit) P.S: im not skilled in linux so if u know some commands to fix it just write them for copy and paste :) P.P.S:Sorry for bad English, im Slovak xD P.P.P.S: Thank so much for any answers update: output from sudo dpkg -l | grep "^rc" richi@Richi-Ubuntu:~/lazarus1.0.12$ sudo dpkg -l | grep "^rc" rc account-plugin-generic-oauth 0.10bzr13.03.26-0ubuntu1.1 amd64 GNOME Control Center account plugin for single signon - generic OAuth rc appmenu-gtk:amd64 12.10.3daily13.04.03-0ubuntu1 amd64 Export GTK menus over DBus rc appmenu-gtk3:amd64 12.10.3daily13.04.03-0ubuntu1 amd64 Export GTK menus over DBus rc fp-compiler-2.6.0 2.6.0-9 amd64 Free Pascal - compiler rc fp-utils-2.6.0 2.6.0-9 amd64 Free Pascal - utilities rc lazarus-ide-0.9.30.4 0.9.30.4-4 amd64 IDE for Free Pascal - common IDE files rc lazarus-ide-1.0.10 1.0.10+dfsg-1 amd64 IDE for Free Pascal - common IDE files rc lcl-utils-0.9.30.4 0.9.30.4-4 amd64 Lazarus Components Library - command line build tools rc lcl-utils-1.0.10 1.0.10+dfsg-1 amd64 Lazarus Components Library - command line build tools rc libbamf3-1:amd64 0.4.0daily13.06.19~13.04-0ubuntu1 amd64 Window matching library - shared library rc libboost-filesystem1.49.0 1.49.0-4 amd64 filesystem operations (portable paths, iteration over directories, etc) in C++ rc libboost-signals1.49.0 1.49.0-4 amd64 managed signals and slots library for C++ rc libboost-system1.49.0 1.49.0-4 amd64 Operating system (e.g. diagnostics support) library rc libboost-thread1.49.0 1.49.0-4 amd64 portable C++ multi-threading rc libbrlapi0.5:amd64 4.4-8ubuntu4 amd64 braille display access via BRLTTY - shared library rc libcamel-1.2-40 3.6.4-0ubuntu1.1 amd64 Evolution MIME message handling library rc libcolumbus0-0 0.4.0daily13.04.16~13.04-0ubuntu1 amd64 error tolerant matching engine - shared library rc libdns95 1:9.9.2.dfsg.P1-2ubuntu2.1 amd64 DNS Shared Library used by BIND rc libdvbpsi7 0.2.2-1 amd64 library for MPEG TS and DVB PSI tables decoding and generating rc libebackend-1.2-5 3.6.4-0ubuntu1.1 amd64 Utility library for evolution data servers rc libedata-book-1.2-15 3.6.4-0ubuntu1.1 amd64 Backend library for evolution address books rc libedata-cal-1.2-18 3.6.4-0ubuntu1.1 amd64 Backend library for evolution calendars rc libgc1c3:amd64 1:7.2d-0ubuntu5 amd64 conservative garbage collector for C and C++ rc libgd2-xpm:amd64 2.0.36~rc1~dfsg-6.1ubuntu1 amd64 GD Graphics Library version 2 rc libgd2-xpm:i386 2.0.36~rc1~dfsg-6.1ubuntu1 i386 GD Graphics Library version 2 rc libgnome-desktop-3-4 3.6.3-0ubuntu1 amd64 Utility library for loading .desktop files - runtime files rc libgphoto2-2:amd64 2.4.14-2 amd64 gphoto2 digital camera library rc libgphoto2-2:i386 2.4.14-2 i386 gphoto2 digital camera library rc libgphoto2-port0:amd64 2.4.14-2 amd64 gphoto2 digital camera port library rc libgphoto2-port0:i386 2.4.14-2 i386 gphoto2 digital camera port library rc libgtksourceview-3.0-0:amd64 3.6.3-0ubuntu1 amd64 shared libraries for the GTK+ syntax highlighting widget rc libgweather-3-1 3.6.2-0ubuntu1 amd64 GWeather shared library rc libharfbuzz0:amd64 0.9.13-1 amd64 OpenType text shaping engine rc libibus-1.0-0:amd64 1.4.2-0ubuntu2 amd64 Intelligent Input Bus - shared library rc libical0 0.48-2 amd64 iCalendar library implementation in C (runtime) rc libimobiledevice3 1.1.4-1ubuntu6.2 amd64 Library for communicating with the iPhone and iPod Touch rc libisc92 1:9.9.2.dfsg.P1-2ubuntu2.1 amd64 ISC Shared Library used by BIND rc libkms1:amd64 2.4.46-1 amd64 Userspace interface to kernel DRM buffer management rc libllvm3.2:i386 1:3.2repack-7ubuntu1 i386 Low-Level Virtual Machine (LLVM), runtime library rc libmikmod2:amd64 3.1.12-5 amd64 Portable sound library rc libpackagekit-glib2-14:amd64 0.7.6-3ubuntu1 amd64 Library for accessing PackageKit using GLib rc libpoppler28:amd64 0.20.5-1ubuntu3 amd64 PDF rendering library rc libraw5:amd64 0.14.7-0ubuntu1.13.04.2 amd64 raw image decoder library rc librhythmbox-core6 2.98-0ubuntu5 amd64 support library for the rhythmbox music player rc libsdl-mixer1.2:amd64 1.2.12-7ubuntu1 amd64 Mixer library for Simple DirectMedia Layer 1.2, libraries rc libsnmp15 5.4.3~dfsg-2.7ubuntu1 amd64 SNMP (Simple Network Management Protocol) library rc libsyncdaemon-1.0-1 4.2.0-0ubuntu1 amd64 Ubuntu One synchronization daemon library rc libunity-core-6.0-5 7.0.0daily13.06.19~13.04-0ubuntu1 amd64 Core library for the Unity interface. rc libusb-0.1-4:i386 2:0.1.12-23.2ubuntu1 i386 userspace USB programming library rc libwayland0:amd64 1.0.5-0ubuntu1 amd64 wayland compositor infrastructure - shared libraries rc linux-image-3.8.0-19-generic 3.8.0-19.30 amd64 Linux kernel image for version 3.8.0 on 64 bit x86 SMP rc linux-image-3.8.0-31-generic 3.8.0-31.46 amd64 Linux kernel image for version 3.8.0 on 64 bit x86 SMP rc linux-image-extra-3.8.0-19-generic 3.8.0-19.30 amd64 Linux kernel image for version 3.8.0 on 64 bit x86 SMP rc linux-image-extra-3.8.0-31-generic 3.8.0-31.46 amd64 Linux kernel image for version 3.8.0 on 64 bit x86 SMP rc screen-resolution-extra 0.15ubuntu1 all Extension for the GNOME screen resolution applet rc unity-common 7.0.0daily13.06.19~13.04-0ubuntu1 all Common files for the Unity interface.

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• Handy ASP.NET MVC 2 Extension Methods &ndash; Where am I?

  - by Bobby Diaz

  Have you ever needed to detect what part of the application is currently being viewed?  This might be a bigger issue if you write a lot of shared/partial views or custom display or editor templates.  Another scenario, which is the one I encountered when I first started down this path, is when you have some type of menu and you’d like to be able to determine which item represents the current page so you can highlight it in some way.  A simple example is the menu that is created as part of the default ASP.NET MVC 2 Application template.   <div id="menucontainer">       <ul id="menu">         <li><%= Html.ActionLink("Home", "Index", "Home") %></li>         <li><%= Html.ActionLink("About", "About", "Home") %></li>     </ul>   </div>   The part that got me at first, however, was the following entry in the default style sheet (Site.css):   ul#menu li.selected a {     background-color: #fff;     color: #000; }   I assumed that the .selected class would automatically get applied to the active menu item.  After trying a few different things, including the MvcContrib MenuBuilder, I decided to write my own extension methods so I would have more control over the output.  First, I needed a way to determine what view the user has navigated to based on the requested URL and route configuration.  Now, I am sure there are many ways to do this, but this is what I came up with:   public static class RequestExtensions {     public static bool IsCurrentRoute(this RequestContext context, String areaName,         String controllerName, params String[] actionNames)     {         var routeData = context.RouteData;         var routeArea = routeData.DataTokens["area"] as String;         var current = false;           if ( ((String.IsNullOrEmpty(routeArea) && String.IsNullOrEmpty(areaName)) ||               (routeArea == areaName)) &&              ((String.IsNullOrEmpty(controllerName)) ||               (routeData.GetRequiredString("controller") == controllerName)) &&              ((actionNames == null) ||                actionNames.Contains(routeData.GetRequiredString("action"))) )         {             current = true;         }           return current;     }       // additional overloads omitted... }   With that in place, I was able to write several UrlHelper methods that check if the supplied values map to the current view.   public static class UrlExtensions {     public static bool IsCurrent(this UrlHelper urlHelper, String areaName,         String controllerName, params String[] actionNames)     {         return urlHelper.RequestContext.IsCurrentRoute(areaName, controllerName, actionNames);     }       public static string Selected(this UrlHelper urlHelper, String areaName,         String controllerName, params String[] actionNames)     {         return urlHelper.IsCurrent(areaName, controllerName, actionNames)             ? "selected" : String.Empty;     }       // additional overloads omitted... }   Now I can re-work the original menu to utilize these new methods.  Note: be sure to import the proper namespace so the extension methods become available inside your views!   <div id="menucontainer">       <ul id="menu">         <li class="<%= Url.Selected(null, "Home", "Index") %>">             <%= Html.ActionLink("Home", "Index", "Home")%></li>           <li class="<%= Url.Selected(null, "Home", "About") %>">             <%= Html.ActionLink("About", "About", "Home")%></li>     </ul>   </div>   If we take it one step further, we can clean up the markup even more.  Check out the Html.ActionMenuItem() extension method and the refined menu:   public static class HtmlExtensions {     public static MvcHtmlString ActionMenuItem(this HtmlHelper htmlHelper, String linkText,         String actionName, String controllerName)     {         var html = new StringBuilder("<li");           if ( htmlHelper.ViewContext.RequestContext                 .IsCurrentRoute(null, controllerName, actionName) )         {             html.Append(" class=\"selected\"");         }           html.Append(">")             .Append(htmlHelper.ActionLink(linkText, actionName, controllerName))             .Append("</li>");           return MvcHtmlString.Create(html.ToString());     }       // additional overloads omitted... }   <div id="menucontainer">       <ul id="menu">         <%= Html.ActionMenuItem("Home", "Index", "Home") %>         <%= Html.ActionMenuItem("About", "About", "Home") %>     </ul>   </div>   Which generates the following HTML:   <div id="menucontainer">       <ul id="menu">         <li class="selected"><a href="/">Home</a></li>         <li><a href="/Home/About">About</a></li>     </ul>   </div>     I have created a codepaste of these extension methods if you are interested in using them in your own projects.  Enjoy!

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• Management and Monitoring Tools for Windows Azure

  - by BuckWoody

  With such a large platform, Windows Azure has a lot of moving parts. We’ve done our best to keep the interface as simple as possible, while giving you the most control and visibility we can. However, as with most Microsoft products, there are multiple ways to do something – and I’ve always found that to be a good strength. Depending on the situation, I might want a graphical interface, a command-line interface, or just an API so I can incorporate the management into my own tools, or have third-party companies write other tools. While by no means exhaustive, I thought I might put together a quick list of a few tools you can use to manage and monitor Windows Azure components, from our IaaS, SaaS and PaaS offerings. Some of the products focus on one area more than another, but all are available today. I’ll try and maintain this list to keep it current, but make sure you check the date of this post’s update – if it’s more than six months old, it’s most likely out of date. Things move fast in the cloud. The Windows Azure Management Portal The primary tool for managing Windows Azure is our portal – most everything you need is there, from creating new services to querying a database. There are two versions as of this writing – a Silverlight client version, and a newer HTML5 version. The latter is being updated constantly to be in parity with the Silverlight client. There’s a balance in this portal between simplicity and power – we’re following the “less is more” approach, with increasing levels of detail as you work through the portal rather than overwhelming you with a single, long “more is more” page. You can find the Portal here: http://windowsazure.com (then click “Log In” and then “Portal”) Windows Azure Management API You can also use programming tools to either write your own interface, or simply provide management functions directly within your solution. You have two options – you can use the more universal REST API’s, which area bit more complex but work with any system that can write to them, or the more approachable .NET API calls in code. You can find the reference for the API’s here: http://msdn.microsoft.com/en-us/library/windowsazure/ee460799.aspx  All Class Libraries, for each part of Windows Azure: http://msdn.microsoft.com/en-us/library/ee393295.aspx  PowerShell Command-lets PowerShell is one of the most powerful scripting languages I’ve used with Windows – and it’s baked into all of our products. When you need to work with multiple servers, scripting is really the only way to go, and the Windows Azure PowerShell Command-Lets allow you to work across most any part of the platform – and can even be used within the services themselves. You can do everything with them from creating a new IaaS, PaaS or SaaS service, to controlling them and even working with security and more. You can find more about the Command-Lets here: http://wappowershell.codeplex.com/documentation (older link, still works, will point you to the new ones as well) We have command-line utilities for other operating systems as well: https://www.windowsazure.com/en-us/manage/downloads/  Video walkthrough of using the Command-Lets: http://channel9.msdn.com/Events/BUILD/BUILD2011/SAC-859T  System Center System Center is actually a suite of graphical tools you can use to manage, deploy, control, monitor and tune software from Microsoft and even other platforms. This will be the primary tool we’ll recommend for managing a hybrid or contiguous management process – and as time goes on you’ll see more and more features put into System Center for the entire Windows Azure suite of products. You can find the Management Pack and README for it here: http://www.microsoft.com/en-us/download/details.aspx?id=11324  SQL Server Management Studio / Data Tools / Visual Studio SQL Server has two built-in management and development, and since Version 2008 R2, you can use them to manage Windows Azure Databases. Visual Studio also lets you connect to and manage portions of Windows Azure as well as Windows Azure Databases. You can read more about Visual Studio here: http://msdn.microsoft.com/en-us/library/windowsazure/ee405484  You can read more about the SQL tools here: http://msdn.microsoft.com/en-us/library/windowsazure/ee621784.aspx  Vendor-Provided Tools Microsoft does not suggest or endorse a specific third-party product. We do, however, use them, and see lots of other customers use them. You can browse to these sites to learn more, and chat with their folks directly on how they support Windows Azure. Cerebrata: Tools for managing from the command-line, graphical diagnostics, graphical storage management - http://www.cerebrata.com/  Quest Cloud Tools: Monitoring, Storage Management, and costing tools - http://communities.quest.com/community/cloud-tools  Paraleap: Monitoring tool - http://www.paraleap.com/AzureWatch  Cloudgraphs: Monitoring too -  http://www.cloudgraphs.com/  Opstera: Monitoring for Windows Azure and a Scale-out pattern manager - http://www.opstera.com/products/Azureops/  Compuware: SaaS performance monitoring, load testing -  http://www.compuware.com/application-performance-management/gomez-apm-products.html  SOASTA: Penetration and Security Testing - http://www.soasta.com/cloudtest/enterprise/  LoadStorm: Load-testing tool - http://loadstorm.com/windows-azure  Open-Source Tools This is probably the most specific set of tools, and the list I’ll have to maintain most often. Smaller projects have a way of coming and going, so I’ll try and make sure this list is current. Windows Azure MMC: (I actually use this one a lot) http://wapmmc.codeplex.com/  Windows Azure Diagnostics Monitor: http://archive.msdn.microsoft.com/wazdmon  Azure Application Monitor: http://azuremonitor.codeplex.com/  Azure Web Log: http://www.xentrik.net/software/azure_web_log.html  Cloud Ninja:Multi-Tennant billing and performance monitor -  http://cnmb.codeplex.com/  Cloud Samurai: Multi-Tennant Management- http://cloudsamurai.codeplex.com/    If you have additions to this list, please post them as a comment and I’ll research and then add them. Thanks!

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• SQL SERVER – Example of Performance Tuning for Advanced Users with DB Optimizer

  - by Pinal Dave

  Performance tuning is such a subject that everyone wants to master it. In beginning everybody is at a novice level and spend lots of time learning how to master the art of performance tuning. However, as we progress further the tuning of the system keeps on getting very difficult. I have understood in my early career there should be no need of ego in the technology field. There are always better solutions and better ideas out there and we should not resist them. Instead of resisting the change and new wave I personally adopt it. Here is a similar example, as I personally progress to the master level of performance tuning, I face that it is getting harder to come up with optimal solutions. In such scenarios I rely on various tools to teach me how I can do things better. Once I learn about tools, I am often able to come up with better solutions when I face the similar situation next time. A few days ago I had received a query where the user wanted to tune it further to get the maximum out of the performance. I have re-written the similar query with the help of AdventureWorks sample database. SELECT * FROM HumanResources.Employee e INNER JOIN HumanResources.EmployeeDepartmentHistory edh ON e.BusinessEntityID = edh.BusinessEntityID INNER JOIN HumanResources.Shift s ON edh.ShiftID = s.ShiftID; User had similar query to above query was used in very critical report and wanted to get best out of the query. When I looked at the query – here were my initial thoughts Use only column in the select statements as much as you want in the application Let us look at the query pattern and data workload and find out the optimal index for it Before I give further solutions I was told by the user that they need all the columns from all the tables and creating index was not allowed in their system. He can only re-write queries or use hints to further tune this query. Now I was in the constraint box – I believe * was not a great idea but if they wanted all the columns, I believe we can’t do much besides using *. Additionally, if I cannot create a further index, I must come up with some creative way to write this query. I personally do not like to use hints in my application but there are cases when hints work out magically and gives optimal solutions. Finally, I decided to use Embarcadero’s DB Optimizer. It is a fantastic tool and very helpful when it is about performance tuning. I have previously explained how it works over here. First open DBOptimizer and open Tuning Job from File >> New >> Tuning Job. Once you open DBOptimizer Tuning Job follow the various steps indicates in the following diagram. Essentially we will take our original script and will paste that into Step 1: New SQL Text and right after that we will enable Step 2 for Generating Various cases, Step 3 for Detailed Analysis and Step 4 for Executing each generated case. Finally we will click on Analysis in Step 5 which will generate the report detailed analysis in the result pan. The detailed pan looks like. It generates various cases of T-SQL based on the original query. It applies various hints and available hints to the query and generate various execution plans of the query and displays them in the resultant. You can clearly notice that original query had a cost of 0.0841 and logical reads about 607 pages. Whereas various options which are just following it has different execution cost as well logical read. There are few cases where we have higher logical read and there are few cases where as we have very low logical read. If we pay attention the very next row to original query have Merge_Join_Query in description and have lowest execution cost value of 0.044 and have lowest Logical Reads of 29. This row contains the query which is the most optimal re-write of the original query. Let us double click over it. Here is the query: SELECT * FROM HumanResources.Employee e INNER JOIN HumanResources.EmployeeDepartmentHistory edh ON e.BusinessEntityID = edh.BusinessEntityID INNER JOIN HumanResources.Shift s ON edh.ShiftID = s.ShiftID OPTION (MERGE JOIN) If you notice above query have additional hint of Merge Join. With the help of this Merge Join query hint this query is now performing much better than before. The entire process takes less than 60 seconds. Please note that it the join hint Merge Join was optimal for this query but it is not necessary that the same hint will be helpful in all the queries. Additionally, if the workload or data pattern changes the query hint of merge join may be no more optimal join. In that case, we will have to redo the entire exercise once again. This is the reason I do not like to use hints in my queries and I discourage all of my users to use the same. However, if you look at this example, this is a great case where hints are optimizing the performance of the query. It is humanly not possible to test out various query hints and index options with the query to figure out which is the most optimal solution. Sometimes, we need to depend on the efficiency tools like DB Optimizer to guide us the way and select the best option from the suggestion provided. Let me know what you think of this article as well your experience with DB Optimizer. Please leave a comment. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Joins, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• ASP.NET MVC: Converting business objects to select list items

  - by DigiMortal

  Some of our business classes are used to fill dropdown boxes or select lists. And often you have some base class for all your business classes. In this posting I will show you how to use base business class to write extension method that converts collection of business objects to ASP.NET MVC select list items without writing a lot of code. BusinessBase, BaseEntity and other base classes I prefer to have some base class for all my business classes so I can easily use them regardless of their type in contexts I need. NB! Some guys say that it is good idea to have base class for all your business classes and they also suggest you to have mappings done same way in database. Other guys say that it is good to have base class but you don’t have to have one master table in database that contains identities of all your business objects. It is up to you how and what you prefer to do but whatever you do – think and analyze first, please. :) To keep things maximally simple I will use very primitive base class in this example. This class has only Id property and that’s it. public class BaseEntity {     public virtual long Id { get; set; } } Now we have Id in base class and we have one more question to solve – how to better visualize our business objects? To users ID is not enough, they want something more informative. We can define some abstract property that all classes must implement. But there is also another option we can use – overriding ToString() method in our business classes. public class Product : BaseEntity {     public virtual string SKU { get; set; }     public virtual string Name { get; set; }       public override string ToString()     {         if (string.IsNullOrEmpty(Name))             return base.ToString();           return Name;     } } Although you can add more functionality and properties to your base class we are at point where we have what we needed: identity and human readable presentation of business objects. Writing list items converter Now we can write method that creates list items for us. public static class BaseEntityExtensions {            public static IEnumerable<SelectListItem> ToSelectListItems<T>         (this IList<T> baseEntities) where T : BaseEntity     {         return ToSelectListItems((IEnumerator<BaseEntity>)                    baseEntities.GetEnumerator());     }       public static IEnumerable<SelectListItem> ToSelectListItems         (this IEnumerator<BaseEntity> baseEntities)     {         var items = new HashSet<SelectListItem>();           while (baseEntities.MoveNext())         {             var item = new SelectListItem();             var entity = baseEntities.Current;               item.Value = entity.Id.ToString();             item.Text = entity.ToString();               items.Add(item);         }           return items;     } } You can see here to overloads of same method. One works with List<T> and the other with IEnumerator<BaseEntity>. Although mostly my repositories return IList<T> when querying data there are always situations where I can use more abstract types and interfaces. Using extension methods in code In your code you can use ToSelectListItems() extension methods like shown on following code fragment. ... var model = new MyFormModel(); model.Statuses = _myRepository.ListStatuses().ToSelectListItems(); ... You can call this method on all your business classes that extend your base entity. Wanna have some fun with this code? Write overload for extension method that accepts selected item ID.

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• Management and Monitoring Tools for Windows Azure

  - by BuckWoody

  With such a large platform, Windows Azure has a lot of moving parts. We’ve done our best to keep the interface as simple as possible, while giving you the most control and visibility we can. However, as with most Microsoft products, there are multiple ways to do something – and I’ve always found that to be a good strength. Depending on the situation, I might want a graphical interface, a command-line interface, or just an API so I can incorporate the management into my own tools, or have third-party companies write other tools. While by no means exhaustive, I thought I might put together a quick list of a few tools you can use to manage and monitor Windows Azure components, from our IaaS, SaaS and PaaS offerings. Some of the products focus on one area more than another, but all are available today. I’ll try and maintain this list to keep it current, but make sure you check the date of this post’s update – if it’s more than six months old, it’s most likely out of date. Things move fast in the cloud. The Windows Azure Management Portal The primary tool for managing Windows Azure is our portal – most everything you need is there, from creating new services to querying a database. There are two versions as of this writing – a Silverlight client version, and a newer HTML5 version. The latter is being updated constantly to be in parity with the Silverlight client. There’s a balance in this portal between simplicity and power – we’re following the “less is more” approach, with increasing levels of detail as you work through the portal rather than overwhelming you with a single, long “more is more” page. You can find the Portal here: http://windowsazure.com (then click “Log In” and then “Portal”) Windows Azure Management API You can also use programming tools to either write your own interface, or simply provide management functions directly within your solution. You have two options – you can use the more universal REST API’s, which area bit more complex but work with any system that can write to them, or the more approachable .NET API calls in code. You can find the reference for the API’s here: http://msdn.microsoft.com/en-us/library/windowsazure/ee460799.aspx  All Class Libraries, for each part of Windows Azure: http://msdn.microsoft.com/en-us/library/ee393295.aspx  PowerShell Command-lets PowerShell is one of the most powerful scripting languages I’ve used with Windows – and it’s baked into all of our products. When you need to work with multiple servers, scripting is really the only way to go, and the Windows Azure PowerShell Command-Lets allow you to work across most any part of the platform – and can even be used within the services themselves. You can do everything with them from creating a new IaaS, PaaS or SaaS service, to controlling them and even working with security and more. You can find more about the Command-Lets here: http://wappowershell.codeplex.com/documentation (older link, still works, will point you to the new ones as well) We have command-line utilities for other operating systems as well: https://www.windowsazure.com/en-us/manage/downloads/  Video walkthrough of using the Command-Lets: http://channel9.msdn.com/Events/BUILD/BUILD2011/SAC-859T  System Center System Center is actually a suite of graphical tools you can use to manage, deploy, control, monitor and tune software from Microsoft and even other platforms. This will be the primary tool we’ll recommend for managing a hybrid or contiguous management process – and as time goes on you’ll see more and more features put into System Center for the entire Windows Azure suite of products. You can find the Management Pack and README for it here: http://www.microsoft.com/en-us/download/details.aspx?id=11324  SQL Server Management Studio / Data Tools / Visual Studio SQL Server has two built-in management and development, and since Version 2008 R2, you can use them to manage Windows Azure Databases. Visual Studio also lets you connect to and manage portions of Windows Azure as well as Windows Azure Databases. You can read more about Visual Studio here: http://msdn.microsoft.com/en-us/library/windowsazure/ee405484  You can read more about the SQL tools here: http://msdn.microsoft.com/en-us/library/windowsazure/ee621784.aspx  Vendor-Provided Tools Microsoft does not suggest or endorse a specific third-party product. We do, however, use them, and see lots of other customers use them. You can browse to these sites to learn more, and chat with their folks directly on how they support Windows Azure. Cerebrata: Tools for managing from the command-line, graphical diagnostics, graphical storage management - http://www.cerebrata.com/  Quest Cloud Tools: Monitoring, Storage Management, and costing tools - http://communities.quest.com/community/cloud-tools  Paraleap: Monitoring tool - http://www.paraleap.com/AzureWatch  Cloudgraphs: Monitoring too -  http://www.cloudgraphs.com/  Opstera: Monitoring for Windows Azure and a Scale-out pattern manager - http://www.opstera.com/products/Azureops/  Compuware: SaaS performance monitoring, load testing -  http://www.compuware.com/application-performance-management/gomez-apm-products.html  SOASTA: Penetration and Security Testing - http://www.soasta.com/cloudtest/enterprise/  LoadStorm: Load-testing tool - http://loadstorm.com/windows-azure  Open-Source Tools This is probably the most specific set of tools, and the list I’ll have to maintain most often. Smaller projects have a way of coming and going, so I’ll try and make sure this list is current. Windows Azure MMC: (I actually use this one a lot) http://wapmmc.codeplex.com/  Windows Azure Diagnostics Monitor: http://archive.msdn.microsoft.com/wazdmon  Azure Application Monitor: http://azuremonitor.codeplex.com/  Azure Web Log: http://www.xentrik.net/software/azure_web_log.html  Cloud Ninja:Multi-Tennant billing and performance monitor -  http://cnmb.codeplex.com/  Cloud Samurai: Multi-Tennant Management- http://cloudsamurai.codeplex.com/    If you have additions to this list, please post them as a comment and I’ll research and then add them. Thanks!

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• WebLogic Server JMS WLST Script – Who is Connected To My Server

  - by james.bayer

  Ever want to know who was connected to your WebLogic Server instance for troubleshooting?  An email exchange about this topic and JMS came up this week, and I’ve heard it come up once or twice before too.  Sometimes it’s interesting or helpful to know the list of JMS clients (IP Addresses, JMS Destinations, message counts) that are connected to a particular JMS server.  This can be helpful for troubleshooting.  Tom Barnes from the WebLogic Server JMS team provided some helpful advice: The JMS connection runtime mbean has “getHostAddress”, which returns the host address of the connecting client JVM as a string.  A connection runtime can contain session runtimes, which in turn can contain consumer runtimes.  The consumer runtime, in turn has a “getDestinationName” and “getMemberDestinationName”.  I think that this means you could write a WLST script, for example, to dump all consumers, their destinations, plus their parent session’s parent connection’s host addresses.    Note that the client runtime mbeans (connection, session, and consumer) won’t necessarily be hosted on the same JVM as a destination that’s in the same cluster (client messages route from their connection host to their ultimate destination in the same cluster). Writing the Script So armed with this information, I decided to take the challenge and see if I could write a WLST script to do this.  It’s always helpful to have the WebLogic Server MBean Reference handy for activities like this.  This one is focused on JMS Consumers and I only took a subset of the information available, but it could be modified easily to do Producers.  I haven’t tried this on a more complex environment, but it works in my simple sandbox case, so it should give you the general idea. # Better to use Secure Config File approach for login as shown here http://buttso.blogspot.com/2011/02/using-secure-config-files-with-weblogic.html connect('weblogic','welcome1','t3://localhost:7001')   # Navigate to the Server Runtime and get the Server Name serverRuntime() serverName = cmo.getName()   # Multiple JMS Servers could be hosted by a single WLS server cd('JMSRuntime/' + serverName + '.jms' ) jmsServers=cmo.getJMSServers()   # Find the list of all JMSServers for this server namesOfJMSServers = '' for jmsServer in jmsServers: namesOfJMSServers = jmsServer.getName() + ' '   # Count the number of connections jmsConnections=cmo.getConnections() print str(len(jmsConnections)) + ' JMS Connections found for ' + serverName + ' with JMSServers ' + namesOfJMSServers   # Recurse the MBean tree for each connection and pull out some information about consumers for jmsConnection in jmsConnections: try: print 'JMS Connection:' print ' Host Address = ' + jmsConnection.getHostAddress() print ' ClientID = ' + str( jmsConnection.getClientID() ) print ' Sessions Current = ' + str( jmsConnection.getSessionsCurrentCount() ) jmsSessions = jmsConnection.getSessions() for jmsSession in jmsSessions: jmsConsumers = jmsSession.getConsumers() for jmsConsumer in jmsConsumers: print ' Consumer:' print ' Name = ' + jmsConsumer.getName() print ' Messages Received = ' + str(jmsConsumer.getMessagesReceivedCount()) print ' Member Destination Name = ' + jmsConsumer.getMemberDestinationName() except: print 'Error retrieving JMS Consumer Information' dumpStack() # Cleanup disconnect() exit() Example Output I expect the output to look something like this and loop through all the connections, this is just the first one: 1 JMS Connections found for AdminServer with JMSServers myJMSServer JMS Connection:   Host Address = 127.0.0.1   ClientID = None   Sessions Current = 16    Consumer:      Name = consumer40      Messages Received = 1      Member Destination Name = myJMSModule!myQueue Notice that it has the IP Address of the client.  There are 16 Sessions open because I’m using an MDB, which defaults to 16 connections, so this matches what I expect.  Let’s see what the full output actually looks like: D:\Oracle\fmw11gr1ps3\user_projects\domains\offline_domain>java weblogic.WLST d:\temp\jms.py   Initializing WebLogic Scripting Tool (WLST) ...   Welcome to WebLogic Server Administration Scripting Shell   Type help() for help on available commands   Connecting to t3://localhost:7001 with userid weblogic ... Successfully connected to Admin Server 'AdminServer' that belongs to domain 'offline_domain'.   Warning: An insecure protocol was used to connect to the server. To ensure on-the-wire security, the SSL port or Admin port should be used instead.   Location changed to serverRuntime tree. This is a read-only tree with ServerRuntimeMBean as the root. For more help, use help(serverRuntime)   1 JMS Connections found for AdminServer with JMSServers myJMSServer JMS Connection: Host Address = 127.0.0.1 ClientID = None Sessions Current = 16 Consumer: Name = consumer40 Messages Received = 2 Member Destination Name = myJMSModule!myQueue Consumer: Name = consumer34 Messages Received = 2 Member Destination Name = myJMSModule!myQueue Consumer: Name = consumer37 Messages Received = 2 Member Destination Name = myJMSModule!myQueue Consumer: Name = consumer16 Messages Received = 2 Member Destination Name = myJMSModule!myQueue Consumer: Name = consumer46 Messages Received = 2 Member Destination Name = myJMSModule!myQueue Consumer: Name = consumer49 Messages Received = 2 Member Destination Name = myJMSModule!myQueue Consumer: Name = consumer43 Messages Received = 1 Member Destination Name = myJMSModule!myQueue Consumer: Name = consumer55 Messages Received = 1 Member Destination Name = myJMSModule!myQueue Consumer: Name = consumer25 Messages Received = 1 Member Destination Name = myJMSModule!myQueue Consumer: Name = consumer22 Messages Received = 1 Member Destination Name = myJMSModule!myQueue Consumer: Name = consumer19 Messages Received = 1 Member Destination Name = myJMSModule!myQueue Consumer: Name = consumer52 Messages Received = 1 Member Destination Name = myJMSModule!myQueue Consumer: Name = consumer31 Messages Received = 1 Member Destination Name = myJMSModule!myQueue Consumer: Name = consumer58 Messages Received = 1 Member Destination Name = myJMSModule!myQueue Consumer: Name = consumer28 Messages Received = 1 Member Destination Name = myJMSModule!myQueue Consumer: Name = consumer61 Messages Received = 1 Member Destination Name = myJMSModule!myQueue Disconnected from weblogic server: AdminServer     Exiting WebLogic Scripting Tool. Thanks to Tom Barnes for the hints and the inspiration to write this up. Image of telephone switchboard courtesy of http://www.JoeTourist.net/ JoeTourist InfoSystems

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• International Radio Operators Alphabet in F# &amp; Silverlight &ndash; Part 1

  - by MarkPearl

  So I have been delving into F# more and more and thought the best way to learn the language is to write something useful. I have been meaning to get some more Silverlight knowledge (up to now I have mainly been doing WPF) so I came up with a really simple project that I can actually use at work. Simply put – I often get support calls from clients wanting new activation codes. One of our main app’s was written in VB6 and had its own “security” where it would require about a 45 character sequence for it to be activated. The catch being that each time you reopen the program it would require a different character sequence, which meant that when we activate clients systems we have to do it live! This involves us either referring them to a website, or reading the characters to them over the phone and since nobody in the office knows the IROA off by heart we would come up with some interesting words to represent characters… 9 times out of 10 the client would type in the wrong character and we would have to start all over again… with this app I am hoping to reduce the errors of reading characters over the phone by treating it like a ham radio. My “Silverlight” application will allow for the user to input a series of characters and the system will then generate the equivalent IROA words… very basic stuff e.g. Character Input – abc Words Generated – Alpha Bravo Charlie After listening to Anders Hejlsberg on Dot Net Rocks Show 541 he mentioned that he felt many applications could make use of F# but in an almost silo basis – meaning that you would write modules that leant themselves to Functional Programming in F# and then incorporate it into a solution where the front end may be in C# or where you would have some other sort of glue. I buy into this kind of approach, so in this project I will use F# to do my very intensive “Business Logic” and will use Silverlight/C# to do the front end. F# Business Layer I am no expert at this, so I am sure to get some feedback on way I could improve my algorithm. My approach was really simple. I would need a function that would convert a single character to a string – i.e. ‘A’ –> “Alpha” and then I would need a function that would take a string of characters, convert them into a sequence of characters, and then apply my converter to return a sequence of words… make sense? Lets start with the CharToString function let CharToString (element:char) = match element.ToString().ToLower() with | "1" -> "1" | "5" -> "5" | "9" -> "9" | "2" -> "2" | "6" -> "6" | "0" -> "0" | "3" -> "3" | "7" -> "7" | "4" -> "4" | "8" -> "8" | "a" -> "Alpha" | "b" -> "Bravo" | "c" -> "Charlie" | "d" -> "Delta" | "e" -> "Echo" | "f" -> "Foxtrot" | "g" -> "Golf" | "h" -> "Hotel" | "i" -> "India" | "j" -> "Juliet" | "k" -> "Kilo" | "l" -> "Lima" | "m" -> "Mike" | "n" -> "November" | "o" -> "Oscar" | "p" -> "Papa" | "q" -> "Quebec" | "r" -> "Romeo" | "s" -> "Sierra" | "t" -> "Tango" | "u" -> "Uniform" | "v" -> "Victor" | "w" -> "Whiskey" | "x" -> "XRay" | "y" -> "Yankee" | "z" -> "Zulu" | element -> "Unknown" Quite simple, an element is passed in, this element is them converted to a lowercase single character string and then matched up with the equivalent word. If by some chance a character is not recognized, “Unknown” will be returned… I know need a function that can take a string and can parse each character of the string and generate a new sequence with the converted words… let ConvertCharsToStrings (s:string) = s |> Seq.toArray |> Seq.map(fun elem -> CharToString(elem)) Here… the Seq.toArray converts the string to a sequence of characters. I then searched for some way to parse through every element in the sequence. Originally I tried Seq.iter, but I think my understanding of what iter does was incorrect. Eventually I found Seq.map, which applies a function to every element in a sequence and then creates a new collection with the adjusted processed element. It turned out to be exactly what I needed… To test that everything worked I created one more function that parsed through every element in a sequence and printed it. AT this point I realized the the Seq.iter would be ideal for this… So my testing code is below… let PrintStrings items = items |> Seq.iter(fun x -> Console.Write(x.ToString() + " ")) let newSeq = ConvertCharsToStrings("acdefg123") PrintStrings newSeq Console.ReadLine()   Pretty basic stuff I guess… I hope my approach was right? In Part 2 I will look into doing a simple Silverlight Frontend, referencing the projects together and deploying….

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• A C# implementation of the CallStream pattern

  - by Bertrand Le Roy

  Dusan published this interesting post a couple of weeks ago about a novel JavaScript chaining pattern: http://dbj.org/dbj/?p=514 It’s similar to many existing patterns, but the syntax is extraordinarily terse and it provides a new form of friction-free, plugin-less extensibility mechanism. Here’s a JavaScript example from Dusan’s post: CallStream("#container") (find, "div") (attr, "A", 1) (css, "color", "#fff") (logger); The interesting thing here is that the functions that are being passed as the first argument are arbitrary, they don’t need to be declared as plug-ins. Compare that with a rough jQuery equivalent that could look something like this: $.fn.logger = function () { /* ... */ } $("selector") .find("div") .attr("A", 1) .css("color", "#fff") .logger(); There is also the “each” method in jQuery that achieves something similar, but its syntax is a little more verbose. Of course, that this pattern can be expressed so easily in JavaScript owes everything to the extraordinary way functions are treated in that language, something Douglas Crockford called “the very best part of JavaScript”. One of the first things I thought while reading Dusan’s post was how I could adapt that to C#. After all, with Lambdas and delegates, C# also has its first-class functions. And sure enough, it works really really well. After about ten minutes, I was able to write this: CallStreamFactory.CallStream (p => Console.WriteLine("Yay!")) (Dump, DateTime.Now) (DumpFooAndBar, new { Foo = 42, Bar = "the answer" }) (p => Console.ReadKey()); Where the Dump function is: public static void Dump(object options) { Console.WriteLine(options.ToString()); } And DumpFooAndBar is: public static void DumpFooAndBar(dynamic options) { Console.WriteLine("Foo is {0} and bar is {1}.", options.Foo, options.Bar); } So how does this work? Well, it really is very simple. And not. Let’s say it’s not a lot of code, but if you’re like me you might need an Advil after that. First, I defined the signature of the CallStream method as follows: public delegate CallStream CallStream (Action<object> action, object options = null); The delegate define a call stream as something that takes an action (a function of the options) and an optional options object and that returns a delegate of its own type. Tricky, but that actually works, a delegate can return its own type. Then I wrote an implementation of that delegate that calls the action and returns itself: public static CallStream CallStream (Action<object> action, object options = null) { action(options); return CallStream; } Pretty nice, eh? Well, yes and no. What we are doing here is to execute a sequence of actions using an interesting novel syntax. But for this to be actually useful, you’d need to build a more specialized call stream factory that comes with some sort of context (like Dusan did in JavaScript). For example, you could write the following alternate delegate signature that takes a string and returns itself: public delegate StringCallStream StringCallStream(string message); And then write the following call stream (notice the currying): public static StringCallStream CreateDumpCallStream(string dumpPath) { StringCallStream str = null; var dump = File.AppendText(dumpPath); dump.AutoFlush = true; str = s => { dump.WriteLine(s); return str; }; return str; } (I know, I’m not closing that stream; sure; bad, bad Bertrand) Finally, here’s how you use it: CallStreamFactory.CreateDumpCallStream(@".\dump.txt") ("Wow, this really works.") (DateTime.Now.ToLongTimeString()) ("And that is all."); Next step would be to combine this contextual implementation with the one that takes an action parameter and do some really fun stuff. I’m only scratching the surface here. This pattern could reveal itself to be nothing more than a gratuitous mind-bender or there could be applications that we hardly suspect at this point. In any case, it’s a fun new construct. Or is this nothing new? You tell me… Comments are open :)

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• Joins in single-table queries

  - by Rob Farley

  Tables are only metadata. They don’t store data. I’ve written something about this before, but I want to take a viewpoint of this idea around the topic of joins, especially since it’s the topic for T-SQL Tuesday this month. Hosted this time by Sebastian Meine (@sqlity), who has a whole series on joins this month. Good for him – it’s a great topic. In that last post I discussed the fact that we write queries against tables, but that the engine turns it into a plan against indexes. My point wasn’t simply that a table is actually just a Clustered Index (or heap, which I consider just a special type of index), but that data access always happens against indexes – never tables – and we should be thinking about the indexes (specifically the non-clustered ones) when we write our queries. I described the scenario of looking up phone numbers, and how it never really occurs to us that there is a master list of phone numbers, because we think in terms of the useful non-clustered indexes that the phone companies provide us, but anyway – that’s not the point of this post. So a table is metadata. It stores information about the names of columns and their data types. Nullability, default values, constraints, triggers – these are all things that define the table, but the data isn’t stored in the table. The data that a table describes is stored in a heap or clustered index, but it goes further than this. All the useful data is going to live in non-clustered indexes. Remember this. It’s important. Stop thinking about tables, and start thinking about indexes. So let’s think about tables as indexes. This applies even in a world created by someone else, who doesn’t have the best indexes in mind for you. I’m sure you don’t need me to explain Covering Index bit – the fact that if you don’t have sufficient columns “included” in your index, your query plan will either have to do a Lookup, or else it’ll give up using your index and use one that does have everything it needs (even if that means scanning it). If you haven’t seen that before, drop me a line and I’ll run through it with you. Or go and read a post I did a long while ago about the maths involved in that decision. So – what I’m going to tell you is that a Lookup is a join. When I run SELECT CustomerID FROM Sales.SalesOrderHeader WHERE SalesPersonID = 285; against the AdventureWorks2012 get the following plan: I’m sure you can see the join. Don’t look in the query, it’s not there. But you should be able to see the join in the plan. It’s an Inner Join, implemented by a Nested Loop. It’s pulling data in from the Index Seek, and joining that to the results of a Key Lookup. It clearly is – the QO wouldn’t call it that if it wasn’t really one. It behaves exactly like any other Nested Loop (Inner Join) operator, pulling rows from one side and putting a request in from the other. You wouldn’t have a problem accepting it as a join if the query were slightly different, such as SELECT sod.OrderQty FROM Sales.SalesOrderHeader AS soh JOIN Sales.SalesOrderDetail as sod on sod.SalesOrderID = soh.SalesOrderID WHERE soh.SalesPersonID = 285; Amazingly similar, of course. This one is an explicit join, the first example was just as much a join, even thought you didn’t actually ask for one. You need to consider this when you’re thinking about your queries. But it gets more interesting. Consider this query: SELECT SalesOrderID FROM Sales.SalesOrderHeader WHERE SalesPersonID = 276 AND CustomerID = 29522; It doesn’t look like there’s a join here either, but look at the plan. That’s not some Lookup in action – that’s a proper Merge Join. The Query Optimizer has worked out that it can get the data it needs by looking in two separate indexes and then doing a Merge Join on the data that it gets. Both indexes used are ordered by the column that’s indexed (one on SalesPersonID, one on CustomerID), and then by the CIX key SalesOrderID. Just like when you seek in the phone book to Farley, the Farleys you have are ordered by FirstName, these seek operations return the data ordered by the next field. This order is SalesOrderID, even though you didn’t explicitly put that column in the index definition. The result is two datasets that are ordered by SalesOrderID, making them very mergeable. Another example is the simple query SELECT CustomerID FROM Sales.SalesOrderHeader WHERE SalesPersonID = 276; This one prefers a Hash Match to a standard lookup even! This isn’t just ordinary index intersection, this is something else again! Just like before, we could imagine it better with two whole tables, but we shouldn’t try to distinguish between joining two tables and joining two indexes. The Query Optimizer can see (using basic maths) that it’s worth doing these particular operations using these two less-than-ideal indexes (because of course, the best indexese would be on both columns – a composite such as (SalesPersonID, CustomerID – and it would have the SalesOrderID column as part of it as the CIX key still). You need to think like this too. Not in terms of excusing single-column indexes like the ones in AdventureWorks2012, but in terms of having a picture about how you’d like your queries to run. If you start to think about what data you need, where it’s coming from, and how it’s going to be used, then you will almost certainly write better queries. …and yes, this would include when you’re dealing with regular joins across multiples, not just against joins within single table queries.

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• SQLAuthority News – 7th Anniversary of Blog – A Personal Note

  - by Pinal Dave

  Special Day Today is a very special day – seven years ago I blogged for the very first time.  Seven years ago, I didn’t know what I was doing, I didn’t know how to blog, or even what a blog was or what to write.  I was working as a DBA, and I was trying to solve a problem – at my job, there were a few issues I had to fix again and again and again.  There were days when I was rewriting the same solution over and over, and there were times when I would get very frustrated because I could not write the same elegant solution that I had written before.  I came up with a solution to this problem – posting these solutions online, where I could access them whenever I needed them.  At that point, I had no idea what a blog was, or even how the internet worked, I had no idea that a blog would be visible to others.  Can you believe it? Google it on Yahoo! After a few posts on this “blog,” there was a surprise for me – an e-mail saying that someone had left me a comment.  I was surprised, because I didn’t even know you could comment on a blog!  I logged on and read my comment.  It said: “I like your script,but there is a small bug.  If you could fix it, it will run on multiple other versions of SQL Server.”  I was like, “wow, someone figured out how to find my blog, and they figured out how to fix my script!”  I found the bug, I fixed the script, and a wrote a thank you note to the guy.  My first question for him was: how did you figure it out – not the script, but how to find my blog?  He said he found it from Yahoo Search (this was in the time before Google, believe it or not). From that day, my life changed.  I wrote a few more posts, I got a few more comments, and I started to watch my traffic.  People were reading, commenting, and giving feedback.  At the end of the day, people enjoyed what I was writing.  This was a fantastic feeling!  I never thought I would be writing for others.  Even today, I don’t feel like I am writing for others, but that I am simply posting what I am learning every day.  From that very first day, I decided that I would not change my intent or my blog’s purpose. 72 Million Views – 2600 Posts – 57000 comments – 10 books – 9 courses Today, this blog is my habit, my addiction, my baby.  Every day I try to learn something new, and that lesson gets posted on the blog.  Lately there have been days where I am traveling for a full 24 hours, but even on those days I try to learn something new, and later when I have free time, I will still post it to the blog.  Because of this habit, this blog has over 72 millions views, I have written more than 2600 posts, and there are 57,000 comments and counting.  I have also written 10 books, 9 courses, and learned so many things.  This blog has given me back so much more than I ever put it into it.  It gave me an education, a reason to learn something new every day, and a way to connect to people.  I like to think of it as a learning chain, a relay where we all pass knowledge from one to another. Never Ending Journey When I started the blog, I thought I would write for a few days and stop, but now after seven years I haven’t stopped and I have no intention of stopping!  However, change happens, and for this blog it will start today.  This blog started as a single resource for SQL Server, but now it has grown beyond, to Sharepoint, Personal Development, Developer Training, MySQL, Big Data, and lots of other things.  Truly speaking, this blog is more than just SQL Server, and that was always my intention.  I named it “SQL Authority,” not “SQL Server Authority”!  Loudly and clearly, I would like to announce that I am going to go back to my roots and start writing more about SQL, more about big data, and more about the other technology like relational databases, MySQL, Oracle, and others.  My goal is not to become a comprehensive resource for every technology, my goal is to learn something new every day – and now it can be so much more than just SQL Server.  I will learn it, and post it here for you. I have written a very long post on this anniversary, but here is the summary: Thank You.  You all have been wonderful.  Seven years is a long journey, and it makes me emotional.  I have been “with” this blog before I met my wife, before we had our daughter.  This blog is like a fourth member of the family.  Keep reading, keep commenting, keep supporting.  Thank you all. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: About Me, MySQL, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority News, T SQL

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• Creating Property Set Expression Trees In A Developer Friendly Way

  - by Paulo Morgado

  In a previous post I showed how to create expression trees to set properties on an object. The way I did it was not very developer friendly. It involved explicitly creating the necessary expressions because the compiler won’t generate expression trees with property or field set expressions. Recently someone contacted me the help develop some kind of command pattern framework that used developer friendly lambdas to generate property set expression trees. Simply putting, given this entity class: public class Person { public string Name { get; set; } } The person in question wanted to write code like this: var et = Set((Person p) => p.Name = "me"); Where et is the expression tree that represents the property assignment. So, if we can’t do this, let’s try the next best thing that is splitting retrieving the property information from the retrieving the value to assign o the property: var et = Set((Person p) => p.Name, () => "me"); And this is something that the compiler can handle. The implementation of Set receives an expression to retrieve the property information from and another expression the retrieve the value to assign to the property: public static Expression<Action<TEntity>> Set<TEntity, TValue>( Expression<Func<TEntity, TValue>> propertyGetExpression, Expression<Func<TValue>> valueExpression) The implementation of this method gets the property information form the body of the property get expression (propertyGetExpression) and the value expression (valueExpression) to build an assign expression and builds a lambda expression using the same parameter of the property get expression as its parameter: public static Expression<Action<TEntity>> Set<TEntity, TValue>( Expression<Func<TEntity, TValue>> propertyGetExpression, Expression<Func<TValue>> valueExpression) { var entityParameterExpression = (ParameterExpression)(((MemberExpression)(propertyGetExpression.Body)).Expression); return Expression.Lambda<Action<TEntity>>( Expression.Assign(propertyGetExpression.Body, valueExpression.Body), entityParameterExpression); } And now we can use the expression to translate to another context or just compile and use it: var et = Set((Person p) => p.Name, () => name); Console.WriteLine(person.Name); // Prints: p => (p.Name = “me”) var d = et.Compile(); d(person); Console.WriteLine(person.Name); // Prints: me It can even support closures: var et = Set((Person p) => p.Name, () => name); Console.WriteLine(person.Name); // Prints: p => (p.Name = value(<>c__DisplayClass0).name) var d = et.Compile(); name = "me"; d(person); Console.WriteLine(person.Name); // Prints: me name = "you"; d(person); Console.WriteLine(person.Name); // Prints: you Not so useful in the intended scenario (but still possible) is building an expression tree that receives the value to assign to the property as a parameter: public static Expression<Action<TEntity, TValue>> Set<TEntity, TValue>(Expression<Func<TEntity, TValue>> propertyGetExpression) { var entityParameterExpression = (ParameterExpression)(((MemberExpression)(propertyGetExpression.Body)).Expression); var valueParameterExpression = Expression.Parameter(typeof(TValue)); return Expression.Lambda<Action<TEntity, TValue>>( Expression.Assign(propertyGetExpression.Body, valueParameterExpression), entityParameterExpression, valueParameterExpression); } This new expression can be used like this: var et = Set((Person p) => p.Name); Console.WriteLine(person.Name); // Prints: (p, Param_0) => (p.Name = Param_0) var d = et.Compile(); d(person, "me"); Console.WriteLine(person.Name); // Prints: me d(person, "you"); Console.WriteLine(person.Name); // Prints: you The only caveat is that we need to be able to write code to read the property in order to write to it.

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• C# async and actors

  - by Alex.Davies

  If you read my last post about async, you might be wondering what drove me to write such odd code in the first place. The short answer is that .NET Demon is written using NAct Actors. Actors are an old idea, which I believe deserve a renaissance under C# 5. The idea is to isolate each stateful object so that only one thread has access to its state at any point in time. That much should be familiar, it's equivalent to traditional lock-based synchronization. The different part is that actors pass "messages" to each other rather than calling a method and waiting for it to return. By doing that, each thread can only ever be holding one lock. This completely eliminates deadlocks, my least favourite concurrency problem. Most people who use actors take this quite literally, and there are plenty of frameworks which help you to create message classes and loops which can receive the messages, inspect what type of message they are, and process them accordingly. But I write C# for a reason. Do I really have to choose between using actors and everything I love about object orientation in C#? Type safety Interfaces Inheritance Generics As it turns out, no. You don't need to choose between messages and method calls. A method call makes a perfectly good message, as long as you don't wait for it to return. This is where asynchonous methods come in. I have used NAct for a while to wrap my objects in a proxy layer. As long as I followed the rule that methods must always return void, NAct queued up the call for later, and immediately released my thread. When I needed to get information out of other actors, I could use EventHandlers and callbacks (continuation passing style, for any CS geeks reading), and NAct would call me back in my isolated thread without blocking the actor that raised the event. Using callbacks looks horrible though. To remind you: m_BuildControl.FilterEnabledForBuilding(    projects,    enabledProjects = m_OutOfDateProjectFinder.FilterNeedsBuilding(        enabledProjects,             newDirtyProjects =             {                 ....... Which is why I'm really happy that NAct now supports async methods. Now, methods are allowed to return Task rather than just void. I can await those methods, and C# 5 will turn the rest of my method into a continuation for me. NAct will run the other method in the other actor's context, but will make sure that when my method resumes, we're back in my context. Neither actor was ever blocked waiting for the other one. Apart from when they were actually busy doing something, they were responsive to concurrent messages from other sources. To be fair, you could use async methods with lock statements to achieve exactly the same thing, but it's ugly. Here's a realistic example of an object that has a queue of data that gets passed to another object to be processed: class QueueProcessor {    private readonly ItemProcessor m_ItemProcessor = ...     private readonly object m_Sync = new object();    private Queue<object> m_DataQueue = ...    private List<object> m_Results = ...     public async Task ProcessOne() {         object data = null;         lock (m_Sync)         {             data = m_DataQueue.Dequeue();         }         var processedData = await m_ItemProcessor.ProcessData(data); lock (m_Sync)         {             m_Results.Add(processedData);         }     } } We needed to write two lock blocks, one to get the data to process, one to store the result. The worrying part is how easily we could have forgotten one of the locks. Compare that to the version using NAct: class QueueProcessorActor : IActor { private readonly ItemProcessor m_ItemProcessor = ... private Queue<object> m_DataQueue = ... private List<object> m_Results = ... public async Task ProcessOne()     {         // We are an actor, it's always thread-safe to access our private fields         var data = m_DataQueue.Dequeue();         var processedData = await m_ItemProcessor.ProcessData(data);         m_Results.Add(processedData);     } } You don't have to explicitly lock anywhere, NAct ensures that your code will only ever run on one thread, because it's an actor. Either way, async is definitely better than traditional synchronous code. Here's a diagram of what a typical synchronous implementation might do: The left side shows what is running on the thread that has the lock required to access the QueueProcessor's data. The red section is where that lock is held, but doesn't need to be. Contrast that with the async version we wrote above: Here, the lock is released in the middle. The QueueProcessor is free to do something else. Most importantly, even if the ItemProcessor sometimes calls the QueueProcessor, they can never deadlock waiting for each other. So I thoroughly recommend you use async for all code that has to wait a while for things. And if you find yourself writing lots of lock statements, think about using actors as well. Using actors and async together really takes the misery out of concurrent programming.

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• Design review for application facing memory issues

  - by Mr Moose

  I apologise in advance for the length of this post, but I want to paint an accurate picture of the problems my app is facing and then pose some questions below; I am trying to address some self inflicted design pain that is now leading to my application crashing due to out of memory errors. An abridged description of the problem domain is as follows; The application takes in a “dataset” that consists of numerous text files containing related data An individual text file within the dataset usually contains approx 20 “headers” that contain metadata about the data it contains. It also contains a large tab delimited section containing data that is related to data in one of the other text files contained within the dataset. The number of columns per file is very variable from 2 to 256+ columns. The original application was written to allow users to load a dataset, map certain columns of each of the files which basically indicating key information on the files to show how they are related as well as identify a few expected column names. Once this is done, a validation process takes place to enforce various rules and ensure that all the relationships between the files are valid. Once that is done, the data is imported into a SQL Server database. The database design is an EAV (Entity-Attribute-Value) model used to cater for the variable columns per file. I know EAV has its detractors, but in this case, I feel it was a reasonable choice given the disparate data and variable number of columns submitted in each dataset. The memory problem Given the fact the combined size of all text files was at most about 5 megs, and in an effort to reduce the database transaction time, it was decided to read ALL the data from files into memory and then perform the following; perform all the validation whilst the data was in memory relate it using an object model Start DB transaction and write the key columns row by row, noting the Id of the written row (all tables in the database utilise identity columns), then the Id of the newly written row is applied to all related data Once all related data had been updated with the key information to which it relates, these records are written using SqlBulkCopy. Due to our EAV model, we essentially have; x columns by y rows to write, where x can by 256+ and rows are often into the tens of thousands. Once all the data is written without error (can take several minutes for large datasets), Commit the transaction. The problem now comes from the fact we are now receiving individual files containing over 30 megs of data. In a dataset, we can receive any number of files. We’ve started seen datasets of around 100 megs coming in and I expect it is only going to get bigger from here on in. With files of this size, data can’t even be read into memory without the app falling over, let alone be validated and imported. I anticipate having to modify large chunks of the code to allow validation to occur by parsing files line by line and am not exactly decided on how to handle the import and transactions. Potential improvements I’ve wondered about using GUIDs to relate the data rather than relying on identity fields. This would allow data to be related prior to writing to the database. This would certainly increase the storage required though. Especially in an EAV design. Would you think this is a reasonable thing to try, or do I simply persist with identity fields (natural keys can’t be trusted to be unique across all submitters). Use of staging tables to get data into the database and only performing the transaction to copy data from staging area to actual destination tables. Questions For systems like this that import large quantities of data, how to you go about keeping transactions small. I’ve kept them as small as possible in the current design, but they are still active for several minutes and write hundreds of thousands of records in one transaction. Is there a better solution? The tab delimited data section is read into a DataTable to be viewed in a grid. I don’t need the full functionality of a DataTable, so I suspect it is overkill. Is there anyway to turn off various features of DataTables to make them more lightweight? Are there any other obvious things you would do in this situation to minimise the memory footprint of the application described above? Thanks for your kind attention.

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• Sort Data in Windows Phone using Collection View Source

  - by psheriff

  When you write a Windows Phone application you will most likely consume data from a web service somewhere. If that service returns data to you in a sort order that you do not want, you have an easy alternative to sort the data without writing any C# or VB code. You use the built-in CollectionViewSource object in XAML to perform the sorting for you. This assumes that you can get the data into a collection that implements the IEnumerable or IList interfaces.For this example, I will be using a simple Product class with two properties, and a list of Product objects using the Generic List class. Try this out by creating a Product class as shown in the following code:public class Product {  public Product(int id, string name)   {    ProductId = id;    ProductName = name;  }  public int ProductId { get; set; }  public string ProductName { get; set; }}Create a collection class that initializes a property called DataCollection with some sample data as shown in the code below:public class Products : List<Product>{  public Products()  {    InitCollection();  }  public List<Product> DataCollection { get; set; }  List<Product> InitCollection()  {    DataCollection = new List<Product>();    DataCollection.Add(new Product(3,        "PDSA .NET Productivity Framework"));    DataCollection.Add(new Product(1,        "Haystack Code Generator for .NET"));    DataCollection.Add(new Product(2,        "Fundamentals of .NET eBook"));    return DataCollection;  }}Notice that the data added to the collection is not in any particular order. Create a Windows Phone page and add two XML namespaces to the Page.xmlns:scm="clr-namespace:System.ComponentModel;assembly=System.Windows"xmlns:local="clr-namespace:WPSortData"The 'local' namespace is an alias to the name of the project that you created (in this case WPSortData). The 'scm' namespace references the System.Windows.dll and is needed for the SortDescription class that you will use for sorting the data. Create a phone:PhoneApplicationPage.Resources section in your Windows Phone page that looks like the following:<phone:PhoneApplicationPage.Resources>  <local:Products x:Key="products" />  <CollectionViewSource x:Key="prodCollection"      Source="{Binding Source={StaticResource products},                       Path=DataCollection}">    <CollectionViewSource.SortDescriptions>      <scm:SortDescription PropertyName="ProductName"                           Direction="Ascending" />    </CollectionViewSource.SortDescriptions>  </CollectionViewSource></phone:PhoneApplicationPage.Resources>The first line of code in the resources section creates an instance of your Products class. The constructor of the Products class calls the InitCollection method which creates three Product objects and adds them to the DataCollection property of the Products class. Once the Products object is instantiated you now add a CollectionViewSource object in XAML using the Products object as the source of the data to this collection. A CollectionViewSource has a SortDescriptions collection that allows you to specify a set of SortDescription objects. Each object can set a PropertyName and a Direction property. As you see in the above code you set the PropertyName equal to the ProductName property of the Product object and tell it to sort in an Ascending direction.All you have to do now is to create a ListBox control and set its ItemsSource property to the CollectionViewSource object. The ListBox displays the data in sorted order by ProductName and you did not have to write any LINQ queries or write other code to sort the data!<ListBox    ItemsSource="{Binding Source={StaticResource prodCollection}}"   DisplayMemberPath="ProductName" />SummaryIn this blog post you learned that you can sort any data without having to change the source code of where the data comes from. Simply feed the data into a CollectionViewSource in XAML and set some sort descriptions in XAML and the rest is done for you! This comes in very handy when you are consuming data from a source where the data is given to you and you do not have control over the sorting.NOTE: You can download this article and many samples like the one shown in this blog entry at my website. http://www.pdsa.com/downloads. Select “Tips and Tricks”, then “Sort Data in Windows Phone using Collection View Source” from the drop down list.Good Luck with your Coding,Paul Sheriff** SPECIAL OFFER FOR MY BLOG READERS **We frequently offer a FREE gift for readers of my blog. Visit http://www.pdsa.com/Event/Blog for your FREE gift!

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• SSIS: Building SQL databases on-the-fly using concatenated SQL scripts

  - by DrJohn

  Over the years I have developed many techniques which help automate the whole SQL Server build process. In my current process, where I need to build entire OLAP data marts on-the-fly, I make regular use of a simple but very effective mechanism to concatenate all the SQL Scripts together from my SSMS (SQL Server Management Studio) projects. This proves invaluable because in two clicks I can redeploy an entire SQL Server database with all tables, views, stored procedures etc. Indeed, I can also use the concatenated SQL scripts with SSIS to build SQL Server databases on-the-fly. You may be surprised to learn that I often redeploy the database several times per day, or even several times per hour, during the development process. This is because the deployment errors are logged and you can quickly see where SQL Scripts have object dependency errors. For example, after changing a table structure you may have forgotten to change any related views. The deployment log immediately points out all the objects which failed to build so you can fix and redeploy the database very quickly. The alternative approach (i.e. doing changes in the database directly using the SSMS UI) would require you to check all dependent objects before making changes. The chances are that you will miss something and wonder why your app returns the wrong data – a common problem caused by changing a table without re-creating dependent views. Using SQL Projects in SSMS A great many developers fail to make use of SQL Projects in SSMS (SQL Server Management Studio). To me they are invaluable way of organizing your SQL Scripts. The screenshot below shows a typical SSMS solution made up of several projects – one project for tables, another for views etc. The key point is that the projects naturally fall into the right order in file system because of the project name. The number in the folder or file name ensures that the projects the SQL scripts are concatenated together in the order that they need to be executed. Hence the script filenames start with 100, 110 etc. Concatenating SQL Scripts To concatenate the SQL Scripts together into one file, I use notepad.exe to create a simple batch file (see example screenshot) which uses the TYPE command to write the content of the SQL Script files into a combined file. As the SQL Scripts are in several folders, I simply use several TYPE command multiple times and append the output together. If you are unfamiliar with batch files, you may not know that the angled bracket (>) means write output of the program into a file. Two angled brackets (>>) means append output of this program into a file. So the command-line DIR > filelist.txt would write the content of the DIR command into a file called filelist.txt. In the example shown above, the concatenated file is called SB_DDS.sql If, like me you place the concatenated file under source code control, then the source code control system will change the file's attribute to "read-only" which in turn would cause the TYPE command to fail. The ATTRIB command can be used to remove the read-only flag. Using SQLCmd to execute the concatenated file Now that the SQL Scripts are all in one big file, we can execute the script against a database using SQLCmd using another batch file as shown below: SQLCmd has numerous options, but the script shown above simply executes the SS_DDS.sql file against the SB_DDS_DB database on the local machine and logs the errors to a file called SB_DDS.log. So after executing the batch file you can simply check the error log to see if your database built without a hitch. If you have errors, then simply fix the source files, re-create the concatenated file and re-run the SQLCmd to rebuild the database. This two click operation allows you to quickly identify and fix errors in your entire database definition.Using SSIS to execute the concatenated file To execute the concatenated SQL script using SSIS, you simply drop an Execute SQL task into your package and set the database connection as normal and then select File Connection as the SQLSourceType (as shown below). Create a file connection to your concatenated SQL script and you are ready to go.   Tips and TricksAdd a new-line at end of every fileThe most common problem encountered with this approach is that the GO statement on the last line of one file is placed on the same line as the comment at the top of the next file by the TYPE command. The easy fix to this is to ensure all your files have a new-line at the end.Remove all USE database statementsThe SQLCmd identifies which database the script should be run against.  So you should remove all USE database commands from your scripts - otherwise you may get unintentional side effects!!Do the Create Database separatelyIf you are using SSIS to create the database as well as create the objects and populate the database, then invoke the CREATE DATABASE command against the master database using a separate package before calling the package that executes the concatenated SQL script.    

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• C#/.NET Little Wonders: Static Char Methods

  - by James Michael Hare

  Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. Often times in our code we deal with the bigger classes and types in the BCL, and occasionally forgot that there are some nice methods on the primitive types as well.  Today we will discuss some of the handy static methods that exist on the char (the C# alias of System.Char) type. The Background I was examining a piece of code this week where I saw the following: 1: // need to get the 5th (offset 4) character in upper case 2: var type = symbol.Substring(4, 1).ToUpper(); 3:  4: // test to see if the type is P 5: if (type == "P") 6: { 7: // ... do something with P type... 8: } Is there really any error in this code?  No, but it still struck me wrong because it is allocating two very short-lived throw-away strings, just to store and manipulate a single char: The call to Substring() generates a new string of length 1 The call to ToUpper() generates a new upper-case version of the string from Step 1. In my mind this is similar to using ToUpper() to do a case-insensitive compare: it isn’t wrong, it’s just much heavier than it needs to be (for more info on case-insensitive compares, see #2 in 5 More Little Wonders). One of my favorite books is the C++ Coding Standards: 101 Rules, Guidelines, and Best Practices by Sutter and Alexandrescu.  True, it’s about C++ standards, but there’s also some great general programming advice in there, including two rules I love:         8. Don’t Optimize Prematurely         9. Don’t Pessimize Prematurely We all know what #8 means: don’t optimize when there is no immediate need, especially at the expense of readability and maintainability.  I firmly believe this and in the axiom: it’s easier to make correct code fast than to make fast code correct.  Optimizing code to the point that it becomes difficult to maintain often gains little and often gives you little bang for the buck. But what about #9?  Well, for that they state: “All other things being equal, notably code complexity and readability, certain efficient design patterns and coding idioms should just flow naturally from your fingertips and are no harder to write then the pessimized alternatives. This is not premature optimization; it is avoiding gratuitous pessimization.” Or, if I may paraphrase: “where it doesn’t increase the code complexity and readability, prefer the more efficient option”. The example code above was one of those times I feel where we are violating a tacit C# coding idiom: avoid creating unnecessary temporary strings.  The code creates temporary strings to hold one char, which is just unnecessary.  I think the original coder thought he had to do this because ToUpper() is an instance method on string but not on char.  What he didn’t know, however, is that ToUpper() does exist on char, it’s just a static method instead (though you could write an extension method to make it look instance-ish). This leads me (in a long-winded way) to my Little Wonders for the day… Static Methods of System.Char So let’s look at some of these handy, and often overlooked, static methods on the char type: IsDigit(), IsLetter(), IsLetterOrDigit(), IsPunctuation(), IsWhiteSpace() Methods to tell you whether a char (or position in a string) belongs to a category of characters. IsLower(), IsUpper() Methods that check if a char (or position in a string) is lower or upper case ToLower(), ToUpper() Methods that convert a single char to the lower or upper equivalent. For example, if you wanted to see if a string contained any lower case characters, you could do the following: 1: if (symbol.Any(c => char.IsLower(c))) 2: { 3: // ... 4: } Which, incidentally, we could use a method group to shorten the expression to: 1: if (symbol.Any(char.IsLower)) 2: { 3: // ... 4: } Or, if you wanted to verify that all of the characters in a string are digits: 1: if (symbol.All(char.IsDigit)) 2: { 3: // ... 4: } Also, for the IsXxx() methods, there are overloads that take either a char, or a string and an index, this means that these two calls are logically identical: 1: // check given a character 2: if (char.IsUpper(symbol[0])) { ... } 3:  4: // check given a string and index 5: if (char.IsUpper(symbol, 0)) { ... } Obviously, if you just have a char, then you’d just use the first form.  But if you have a string you can use either form equally well. As a side note, care should be taken when examining all the available static methods on the System.Char type, as some seem to be redundant but actually have very different purposes.  For example, there are IsDigit() and IsNumeric() methods, which sound the same on the surface, but give you different results. IsDigit() returns true if it is a base-10 digit character (‘0’, ‘1’, … ‘9’) where IsNumeric() returns true if it’s any numeric character including the characters for ½, ¼, etc. Summary To come full circle back to our opening example, I would have preferred the code be written like this: 1: // grab 5th char and take upper case version of it 2: var type = char.ToUpper(symbol[4]); 3:  4: if (type == 'P') 5: { 6: // ... do something with P type... 7: } Not only is it just as readable (if not more so), but it performs over 3x faster on my machine:    1,000,000 iterations of char method took: 30 ms, 0.000050 ms/item.    1,000,000 iterations of string method took: 101 ms, 0.000101 ms/item. It’s not only immediately faster because we don’t allocate temporary strings, but as an added bonus there less garbage to collect later as well.  To me this qualifies as a case where we are using a common C# performance idiom (don’t create unnecessary temporary strings) to make our code better. Technorati Tags: C#,CSharp,.NET,Little Wonders,char,string

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• Writing an ASP.Net Web based TFS Client

  - by Glav

  So one of the things I needed to do was write an ASP.Net MVC based application for our senior execs to manage a set of arbitrary attributes against stories, bugs etc to be able to attribute whether the item was related to Research and Development, and if so, what kind. We are using TFS Azure and don’t have the option of custom templates. I have decided on using a string based field within the template that is not very visible and which we don’t use to write a small set of custom which will determine the research and development association. However, this string munging on the field is not very user friendly so we need a simple tool that can display attributes against items in a simple dropdown list or something similar. Enter a custom web app that accesses our TFS items in Azure (Note: We are also using Visual Studio 2012) Now TFS Azure uses your Live ID and it is not really possible to easily do this in a server based app where no interaction is available. Even if you capture the Live ID credentials yourself and try to submit them to TFS Azure, it wont work. Bottom line is that it is not straightforward nor obvious what you have to do. In fact, it is a real pain to find and there are some answers out there which don’t appear to be answers at all given they didn’t work in my scenario. So for anyone else who wants to do this, here is a simple breakdown on what you have to do: Go here and get the “TFS Service Credential Viewer”. Install it, run it and connect to your TFS instance in azure and create a service account. Note the username and password exactly as it presents it to you. This is the magic identity that will allow unattended, programmatic access. Without this step, don’t bother trying to do anything else. In your MVC app, reference the following assemblies from “C:\Program Files (x86)\Microsoft Visual Studio 11.0\Common7\IDE\ReferenceAssemblies\v2.0”: Microsoft.TeamFoundation.Client.dll Microsoft.TeamFoundation.Common.dll Microsoft.TeamFoundation.VersionControl.Client.dll Microsoft.TeamFoundation.VersionControl.Common.dll Microsoft.TeamFoundation.WorkItemTracking.Client.DataStoreLoader.dll Microsoft.TeamFoundation.WorkItemTracking.Client.dll Microsoft.TeamFoundation.WorkItemTracking.Common.dll If hosting this in Internet Information Server, for the application pool this app runs under, you will need to enable 32 Bit support. You also have to allow the TFS client assemblies to store a cache of files on your system. If you don’t do this, you will authenticate fine, but then get an exception saying that it is unable to access the cache at some directory path when you query work items. You can set this up by adding the following to your web.config, in the <appSettings> element as shown below: <appSettings> <!-- Add reference to TFS Client Cache --> <add key="WorkItemTrackingCacheRoot" value="C:\windows\temp" /> </appSettings> With all that in place, you can write the following code: var token = new Microsoft.TeamFoundation.Client.SimpleWebTokenCredential("{you-service-account-name", "{your-service-acct-password}"); var clientCreds = new Microsoft.TeamFoundation.Client.TfsClientCredentials(token); var currentCollection = new TfsTeamProjectCollection(new Uri(“https://{yourdomain}.visualstudio.com/defaultcollection”), clientCreds); TfsConfigurationServercurrentCollection.EnsureAuthenticated(); In the above code, not the URL contains the “defaultcollection” at the end of the URL. Obviously replace {yourdomain} with whatever is defined for your TFS in Azure instance. In addition, make sure the service user account and password that was generated in the first step is substituted in here. Note: If something is not right, the “EnsureAuthenticated()” call will throw an exception with the message being you are not authorised. If you forget the “defaultcollection” on the URL, it will still fail but with a message saying you are not authorised. That is, a similar but different exception message. And that is it. You can then query the collection using something like: var service = currentCollection.GetService<WorkItemStore>(); var proj = service.Projects[0]; var allQueries = proj.StoredQueries; for (int qcnt = 0; qcnt < allQueries.Count; qcnt++) {     var query = allQueries[qcnt];     var queryDesc = string.format(“Query found named: {0}”,query.Name); } You get the idea. If you search around, you will find references to the ServiceIdentityCredentialProvider which is referenced in this article. I had no luck with this method and it all looked too hard since it required an extra KB article and other magic sauce. So I hope that helps. This article certainly would have helped me save a boat load of time and frustration.

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• My Red Gate Experience

  - by Colin Rothwell

  I’m Colin, and I’ve been an intern working with Mike in publishing on Simple-Talk and SQLServerCentral for the past ten weeks. I’ve mostly been working “behind the scenes”, making improvements to the spam filtering, along with various other small tweaks. When I arrived at Red Gate, one of the first things Mike asked me was what I wanted to get out of the internship. It wasn’t a question I’d given a great deal of thought to, but my immediate response was the same as almost anybody: to support my growing family. Well, ok, not quite that, but money was certainly a motivator, along with simply making sure that I didn’t get bored over the summer. Three months is a long time to fill, and many of my friends end up getting bored, or worse, knitting obsessively. With the arrogance which seems fairly common among Cambridge people, I wasn’t expecting to really learn much here! In my mind, the part of the year where I am at Uni is the part where I learn things, whilst Red Gate would be an opportunity to apply what I’d learnt. Thankfully, the opposite is true: I’ve learnt a lot during my time here, and there has been a definite positive impact on the way I write code. The first thing I’ve really learnt is that test-driven development is, in general, a sensible way of working. Before coming, I didn’t really get it: how could you test something you hadn’t yet written? It didn’t make sense! My problem was seeing a test as having to test all the behaviour of a given function. Writing tests which test the bare minimum possible and building them up is a really good way of crystallising the direction the code needs to grow in, and ensures you never attempt to write too much code at time. One really good experience of this was early on in my internship when Mike and I were working on the query used to list active authors: I’d written something which I thought would do the trick, but by starting again using TDD we grew something which revealed that there were several subtle mistakes in the query I’d written. I’ve also been awakened to the value of pair programming. Whilst I could sort of see the point before coming, I also thought that it was impossible that two people would ever get more done at the same computer than if they were working separately. I still think that this is true for projects with pieces that developers can easily work on independently, and with developers who both know the codebase, but I’ve found that pair programming can be really good for learning a code base, and for building up small projects to the point where you can start working on separate components, as well as solving particularly difficult problems. Later on in my internship, for my down tools week project, I was working on adding Python support to Glimpse. Another intern and I we pair programmed the entire project, using ping pong pair programming as much as possible. One bonus that this brought which I wasn’t expecting was that I found myself less prone to distraction: with someone else peering over my shoulder, I didn’t have the ever-present temptation to open gmail, or facebook, or yammer, or twitter, or hacker news, or reddit, and so on, and so forth. I’m quite proud of this project: I think it’s some of the best code I’ve written. I’ve also been really won over to the value of descriptive variables names. In my pre-Red Gate life, as a lone-ranger style cowboy programmer, I’d developed a tendency towards laziness in variable names, sometimes abbreviating or, worse, using acronyms. I’ve swiftly realised that this is a bad idea when working with a team: saving a few key strokes is inevitably not worth it when it comes to reading code again in the future. Longer names also mean you can do away with a majority of comments. I appreciate that if you’ve come up with an O(n*log n) algorithm for something which seemed O(n^2), you probably want to explain how it works, but explaining what a variable name means is a big no no: it’s so very easy to change the behaviour of the code, whilst forgetting about the comments. Whilst at Red Gate, I took the opportunity to attend a code retreat, which really helped me to solidify all the things I’d learnt. To be completely free of any existing code base really lets you focus on best practises and think about how you write code. If you get a chance to go on a similar event, I’d highly recommend it! Cycling to Red Gate, I’ve also become much better at fitting inner tubes: if you’re struggling to get the tube out, or re-fit the tire, letting a bit of air out usually helps. I’ve also become quite a bit better at foosball and will miss having a foosball table! I’d like to finish off by saying thank you to everyone at Red Gate for having me. I’ve really enjoyed working with, and learning from, the team that brings you this web site. If you meet any of them, buy them a drink!

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