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• My First Weeks at Red Gate

  - by Jess Nickson

  Hi, my name’s Jess and early September 2012 I started working at Red Gate as a Software Engineer down in The Agency (the Publishing team). This was a bit of a shock, as I didn’t think this team would have any developers! I admit, I was a little worried when it was mentioned that my role was going to be different from normal dev. roles within the company. However, as luck would have it, I was placed within a team that was responsible for the development and maintenance of Simple-Talk and SQL Server Central (SSC). I felt rather unprepared for this role. I hadn’t used many of the technologies involved and of those that I had, I hadn’t looked at them for quite a while. I was, nevertheless, quite excited about this turn of events. As I had predicted, the role has been quite challenging so far. I expected that I would struggle to get my head round the large codebase already in place, having never used anything so much as a fraction of the size of this before. However, I was perhaps a bit naive when it came to how quickly things would move. I was required to start learning/remembering a number of different languages and technologies within time frames I would never have tried to set myself previously. Having said that, my first week was pretty easy. It was filled with meetings that were designed to get the new starters up to speed with the different departments, ideals and rules within the company. I also attended some lightning talks being presented by other employees, which were pretty useful. These occur once a fortnight and normally consist of around four speakers. In my spare time, we set up the Simple-Talk codebase on my computer and I started exploring it and worked on my first feature – redirecting requests for URLs that used incorrect casing! It was also during this time that I was given my first introduction to test-driven development (TDD) with Michael via a code kata. Although I had heard of the general ideas behind TDD, I had definitely never tried it before. Indeed, I hadn’t really done any automated testing of code before, either. The session was therefore very useful and gave me insights as to some of the coding practices used in my team. Although I now understand the importance of TDD, it still seems odd in my head and I’ve yet to master how to sensibly step up the functionality of the code a bit at a time. The second week was both easier and more difficult than the first. I was given a new project to work on, meaning I was no longer using the codebase already in place. My job was to take some designs, a WordPress theme, and some initial content and build a page that allowed users of the site to read provided resources and give feedback. This feedback could include their thoughts about the resource, the topics covered and the page design itself. Although it didn’t sound the most challenging of projects when compared to fixing bugs in our current codebase, it nevertheless provided a few sneaky problems that had me stumped. I really enjoyed working on this project as it allowed me to play around with HTML, CSS and JavaScript; all things that I like working with but rarely have a chance to use. I completed the aims for the project on time and was happy with the final outcome – though it still needs a good designer to take a look at it! I am now into my third week at Red Gate and I have temporarily been pulled off the website from week 2. I am again back to figuring out the Simple-Talk codebase. Monday provided me with the chance to learn a bunch of new things: system level testing, Selenium and Python. I was set the challenge of testing a bug fix dealing with the search bars in Simple-Talk. The exercise was pretty fun, although Mike did have to point me in the right direction when I started making the tests a bit too complex. The rest of the week looks set to be focussed on pair programming with Mike as we work together on a new feature. I look forward to the challenges that still face me and hope that I will be able to get up to speed quickly. *fingers crossed*

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• VB Myth - Case Insensitivity is Awesome!

  - by Damon

  I was reading Andy Brown's article 10 Reasons Why Visual Basic is Better than C# and the first claim is that VB is superior because of case insensitivity.  I think the reasons he outlines are basically as follows: Your fingers get tired finding the shift key (e.g. typing PascalCase and camelCase members) You are much more likely to make mistakes while typing names When you accidentally leave caps lock on, it really matters These three arguments culminate in the conclusion: "It doesn't matter if you disagree with everything else in this article: case-sensitivity alone is sufficient reason to ditch C#!" Righto.  I've been using Visual Basic since version 5.0, I wrote a book about ASP.NET in Visual Basic, so I want everyone to know I'm definitely not a VB.NET hater.  I had to converted to C# because it was the language of preference at the places I've worked, so I'm used to both languages.  I love me some case sensitivity.  So first, let's debunk the claims. First, your fingers do not get tired of finding the shift key unless you are writing code in notepad and compiling everything on the command line.  Visual Studio pretty much takes away the need to use the shift key at all. For the most part, any programmer worth a damn doesn't have to type more than about 3-5 characters of any variable or method name before IntelliSense kicks in to help.  VB or C#, if you are not using the tab key for autocomplete then you are typing too much anyway, regardless of whether the shift key is involved or not.  Also, you've got to be a pretty hard-core candy ass if you're complaining at the end of the day that your little fingers are hurting from hitting the shift key. Second, I cannot logically refute the fact that if there are more stringent rules about case sensitivity it will lead to more mistakes.  As such, know that you will be more prone to mistakes in C#.  However, lets talk about the magnitude of the problem.  If you are using IntelliSense then you have auto-correction built in so you probably won't have much of a problem in the first place.  If you manage to bypass IntelliSense and type something wrong you normally are immediately presented with a red-squiggly to let you know something is amiss.  Normally, a person would look at the problem, figure out what the heck went wrong, and then avoid that problem again in the future.  Granted, I have met people who seem to lack this capability, but their problem is deeper than a decision between VB.NET and C#.  So let's make sure that we're all on the same page about this problem.  If you have two teams of developers, one that uses VB.NET and one that uses C#, do not expect to see the VB.NET team drinking beer at the end of the project in festive revelry while the C# team is crying over what the hell to do because their code is riddled with case-sensitivity problems that nobody can resolve. Lastly, if you leave your caps lock key on, turn it off.  Really, what kind of ass-hat would write an entire VB.NET application ENTIRELY IN CAPS?  I happen to be a fan of case sensitivity because it encourages precision and uniformity.  The last thing I need is a code base that looks like it was ransacked by LeEt HacKors wHo Can uSe wHateVer cASe tHey wanT.  I mean really, if you saw someone write this: PuBLIc Sub MyMethod . End Sub And upon asking them why BL was upper case, they responded "Oh, I accidentally hit the shift key there.  Fortunately for me VB.NET is a case insensitive language so I saved a couple of keystrokes by leaving it in there."  Or if you saw: PUBLIC SUB ANOTHERMETHOD . END SUB And the response to why it was uppercased was "Yeah, I accidentally had caps locks on, fortunately for me VB.NET doesn't care.  Really dodged a bullet there, glad I wasn't using C#."  Would you not think that a bit ridiculous?  If you want to convince C# developers that C# sucks, go for it.  But the case insensitivity argument is crap.

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• Getting App.config to be configuration specific in VS2010

  - by MarkPearl

  I recently wanted to have a console application that had configuration specific settings. For instance, if I had two configurations “Debug” and “Release”, depending on the currently selected configuration I wanted it to use a specific configuration file (either debug or config). If you are wanting to do something similar, here is a potential solution that worked for me. Setting up a demo app to illustrate the point First, let’s set up an application that will demonstrate the most basic concept. using System; using System.Configuration; namespace ConsoleSpecificConfiguration { class Program { static void Main(string[] args) { Console.WriteLine("Config"); Console.WriteLine(ConfigurationManager.AppSettings["Example Config"]); Console.ReadLine(); } } }   This does a really simple thing. Display a config when run. To do this, you also need a config file set up. My default looks as follows… <?xml version="1.0" encoding="utf-8" ?> <configuration> <appSettings> <add key="Example Config" value="Default"/> </appSettings> </configuration>   Your entire solution will look as follows… Running the project you will get the following amazing output…   Let’s now say instead of having one config file we want depending on whether we are running in “Debug” or “Release” for the solution configuration we want different config settings to be propagated across you can do the following… Step 1 – Create alternate config Files First add additional config files to your solution. You should have some form of naming convention for these config files, I have decided to follow a similar convention to the one used for web.config, so in my instance I am going to add a App.Debug.config and a App.Release.config file BUT you can follow any naming convention you want provided you wire up the rest of the approach to use this convention. My files look as follows.. App.Debug.config <?xml version="1.0" encoding="utf-8" ?> <configuration> <appSettings> <add key="Example Config" value="Debug"/> </appSettings> </configuration>   App.Release.config <?xml version="1.0" encoding="utf-8" ?> <configuration> <appSettings> <add key="Example Config" value="Release"/> </appSettings> </configuration>   Your solution will now look as follows… Step 2 – Create a bat file that will overwrite files The next step is to create a bat file that will overwrite one file with another. If you right click on the solution in the solution explorer there will be a menu option to add new items to the solution. Create a text file called “copyifnewer.bat” which will be our copy script. It’s contents should look as follows… @echo off echo Comparing two files: %1 with %2 if not exist %1 goto File1NotFound if not exist %2 goto File2NotFound fc %1 %2 /A if %ERRORLEVEL%==0 GOTO NoCopy echo Files are not the same. Copying %1 over %2 copy %1 %2 /y & goto END :NoCopy echo Files are the same. Did nothing goto END :File1NotFound echo %1 not found. goto END :File2NotFound copy %1 %2 /y goto END :END echo Done. Your solution should now look as follows…   Step 3 – Customize the Post Build event command line We now need to wire up everything – which we will do using the post build event command line in VS2010. Right click on your project and go to it’s properties We are now going to wire up the script so that when we build our project it will overwrite the default App.config with whatever file we want. The syntax goes as follows… call "$(SolutionDir)copyifnewer.bat" "$(ProjectDir)App.$(ConfigurationName).config" "$(ProjectDir)$(OutDir)\$(TargetFileName).config" Testing it If I now change my project configuration to Release   And then run my application I get the following output… Toggling between Release and Debug mode will show that the config file is changing each time. And that is it!

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• Functional Adaptation

  - by Charles Courchaine

  In real life and OO programming we’re often faced with using adapters, DVI to VGA, 1/4” to 1/8” audio connections, 110V to 220V, wrapping an incompatible interface with a new one, and so on.  Where the adapter pattern is generally considered for interfaces and classes a similar technique can be applied to method signatures.  To be fair, this adaptation is generally used to reduce the number of parameters but I’m sure there are other clever possibilities to be had.  As Jan questioned in the last post, how can we use a common method to execute an action if the action has a differing number of parameters, going back to the greeting example it was suggested having an AddName method that takes a first and last name as parameters.  This is exactly what we’ll address in this post. Let’s set the stage with some review and some code changes.  First, our method that handles the setup/tear-down infrastructure for our WCF service: 1: private static TResult ExecuteGreetingFunc<TResult>(Func<IGreeting, TResult> theGreetingFunc) 2: { 3: IGreeting aGreetingService = null; 4: try 5: { 6: aGreetingService = GetGreetingChannel(); 7: return theGreetingFunc(aGreetingService); 8: } 9: finally 10: { 11: CloseWCFChannel((IChannel)aGreetingService); 12: } 13: } Our original AddName method: 1: private static string AddName(string theName) 2: { 3: return ExecuteGreetingFunc<string>(theGreetingService => theGreetingService.AddName(theName)); 4: } Our new AddName method: 1: private static int AddName(string firstName, string lastName) 2: { 3: return ExecuteGreetingFunc<int>(theGreetingService => theGreetingService.AddName(firstName, lastName)); 4: } Let’s change the AddName method, just a little bit more for this example and have it take the greeting service as a parameter. 1: private static int AddName(IGreeting greetingService, string firstName, string lastName) 2: { 3: return greetingService.AddName(firstName, lastName); 4: } The new signature of AddName using the Func delegate is now Func<IGreeting, string, string, int>, which can’t be used with ExecuteGreetingFunc as is because it expects Func<IGreeting, TResult>.  Somehow we have to eliminate the two string parameters before we can use this with our existing method.  This is where we need to adapt AddName to match what ExecuteGreetingFunc expects, and we’ll do so in the following progression. 1: Func<IGreeting, string, string, int> -> Func<IGreeting, string, int> 2: Func<IGreeting, string, int> -> Func<IGreeting, int>   For the first step, we’ll create a method using the lambda syntax that will “eliminate” the last name parameter: 1: string lastNameToAdd = "Smith"; 2: //Func<IGreeting, string, string, int> -> Func<IGreeting, string, int> 3: Func<IGreeting, string, int> addName = (greetingService, firstName) => AddName(greetingService, firstName, lastNameToAdd); The new addName method gets us one step close to the signature we need.  Let’s say we’re going to call this in a loop to add several names, we’ll take the final step from Func<IGreeting, string, int> -> Func<IGreeting, int> in line as a lambda passed to ExecuteGreetingFunc like so: 1: List<string> firstNames = new List<string>() { "Bob", "John" }; 2: int aID; 3: foreach (string firstName in firstNames) 4: { 5: //Func<IGreeting, string, int> -> Func<IGreeting, int> 6: aID = ExecuteGreetingFunc<int>(greetingService => addName(greetingService, firstName)); 7: Console.WriteLine(GetGreeting(aID)); 8: } If for some reason you needed to break out the lambda on line 6 you could replace it with 1: aID = ExecuteGreetingFunc<int>(ApplyAddName(addName, firstName)); and use this method: 1: private static Func<IGreeting, int> ApplyAddName(Func<IGreeting, string, int> addName, string lastName) 2: { 3: return greetingService => addName(greetingService, lastName); 4: } Splitting out a lambda into its own method is useful both in this style of coding as well as LINQ queries to improve the debugging experience.  It is not strictly necessary to break apart the steps & functions as was shown above; the lambda in line 6 (of the foreach example) could include both the last name and first name instead of being composed of two functions.  The process demonstrated above is one of partially applying functions, this could have also been done with Currying (also see Dustin Campbell’s excellent post on Currying for the canonical curried add example).  Matthew Podwysocki also has some good posts explaining both Currying and partial application and a follow up post that further clarifies the difference between Currying and partial application.  In either technique the ultimate goal is to reduce the number of parameters passed to a function.  Currying makes it a single parameter passed at each step, where partial application allows one to use multiple parameters at a time as we’ve done here.  This technique isn’t for everyone or every problem, but can be extremely handy when you need to adapt a call to something you don’t control.

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• Professional Development – Difference Between Bio, CV and Resume

  - by Pinal Dave

  Applying for work can be very stressful – you want to put your best foot forward, and it can be very hard to sell yourself to a potential employer while highlighting your best characteristics and answering questions.  On top of that, some jobs require different application materials – a biography (or bio), a curriculum vitae (or CV), or a resume.  These things seem so interchangeable, so what is the difference? Let’s start with the one most of us have heard of – the resume.  A resume is a summary of your job and education history.  If you have ever applied for a job, you will have used a resume.  The ability to write a good resume that highlights your best characteristics and emphasizes your qualifications for a specific job is a skill that will take you a long way in the world.  For such an essential skill, unfortunately it is one that many people struggle with. RESUME So let’s discuss what makes a great resume.  First, make sure that your name and contact information are at the top, in large print (slightly larger font than the rest of the text, size 14 or 16 if the rest is size 12, for example).  You need to make sure that if you catch the recruiter’s attention and they know how to get a hold of you. As for qualifications, be quick and to the point.  Make your job title and the company the headline, and include your skills, accomplishments, and qualifications as bullet points.  Use good action verbs, like “finished,” “arranged,” “solved,” and “completed.”  Include hard numbers – don’t just say you “changed the filing system,” say that you “revolutionized the storage of over 250 files in less than five days.”  Doesn’t that sentence sound much more powerful? Curriculum Vitae (CV) Now let’s talk about curriculum vitae, or “CVs”.  A CV is more like an expanded resume.  The same rules are still true: put your name front and center, keep your contact info up to date, and summarize your skills with bullet points.  However, CVs are often required in more technical fields – like science, engineering, and computer science.  This means that you need to really highlight your education and technical skills. Difference between Resume and CV Resumes are expected to be one or two pages long – CVs can be as many pages as necessary.  If you are one of those people lucky enough to feel limited by the size constraint of resumes, a CV is for you!  On a CV you can expand on your projects, highlight really exciting accomplishments, and include more educational experience – including GPA and test scores from the GRE or MCAT (as applicable).  You can also include awards, associations, teaching and research experience, and certifications.  A CV is a place to really expand on all your experience and how great you will be in this particular position. Biography (Bio) Chances are, you already know what a bio is, and you have even read a few of them.  Think about the one or two paragraphs that every author includes in the back flap of a book.  Think about the sentences under a blogger’s photo on every “About Me” page.  That is a bio.  It is a way to quickly highlight your life experiences.  It is essentially the way you would introduce yourself at a party. Where a bio is required for a job, chances are they won’t want to know about where you were born and how many pets you have, though.  This is a way to summarize your entire job history in quick-to-read format – and sometimes during a job hunt, being able to get to the point and grab the recruiter’s interest is the best way to get your foot in the door.  Think of a bio as your entire resume put into words. Most bios have a standard format.  In paragraph one, talk about your most recent position and accomplishments there, specifically how they relate to the job you are applying for.  If you have teaching or research experience, training experience, certifications, or management experience, talk about them in paragraph two.  Paragraph three and four are for highlighting publications, education, certifications, associations, etc.  To wrap up your bio, provide your contact info and availability (dates and times). Where to use What? For most positions, you will know exactly what kind of application to use, because the job announcement will state what materials are needed – resume, CV, bio, cover letter, skill set, etc.  If there is any confusion, choose whatever the industry standard is (CV for technical fields, resume for everything else) or choose which of your documents is the strongest. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: About Me, PostADay, Professional Development, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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• When does "proper" programming no longer matter?

  - by Kai Qing

  I've been a full time programmer for about 8 years now. Web based mostly, ranging in weird jobs for clients. Never anything I "want" to do. So my experience is limited to what I've been contracted to do, having no real incentive to master anything in particular. So here's my scenario and ultimately what I wonder about... I've been building an android game in my spare time. It's using the libgdx library so quite a bit of the heavy lifting is done for me. I don't read much of the docs cause unless it's in tutorial format I will just not care, and ultimately most of my questions have already been asked on stackoverflow. I get along fine and my game works as expected... Suspiciously well, even. So much so that I wonder why one should bother to be "proper" when coding if the end result is ultimately the same. To be more specific, I used a hashtable because I wanted something close to an associative array. Human readable key values. In other places to achieve similar things, I use a vector. I know libgdx has vector2 and vector3 classes, but I've never used them. When I come across weird problems and search stackoverflow for help, I see a lot of people just reaming the questions that use a certain datatype when another one is technically "proper." Like using an ArrayList because it does not require defined bounds versus re-defining an int[] with new known boundaries. Or even something trivial like this: for(int i = 0; i < items.length; i ++) { // do something } I know it evaluates item.length on every iteration. I just don't care. I know items will never be more than 15 to 20 items. So why bother caring if I evaluate items.length on every iteration? So I wonder - why does everyone get all up in arms over this? Who cares if I use a less efficient datatype to get the job done? I ran some tests to see how the app performs using the lazy, get it done fast and don't look back method I just described versus the proper, follow the tutorial and use the exact data types suggested by the community. The results: Same thing. Average 45 fps. I opened every app on the phone and galaxy tab. Same deal. No difference. My game is pretty graphic intensive. It's not like it's just a simple thing. I expected it to perform kind of badly since I don't care to optimize image assets or... well, you probably get the idea. I'm making the game for fun. As a joke, really. But in doing so I'm working outside the normal scope of my job, which is to always follow the rules and do it the right way. So to say, I am without bounds here and this has caused me to wonder why I ever really care to be "proper" So I guess my question to you is this: Is there a threshold when it no longer matters to be proper? Is there a lasting, longer term consequence to the lazy, get it done and don't look back route? Is it ok to say - "so long as it gets the job done, I don't care?" Disclaimer: When I program my game, I am almost always drunk. I do it to remember why I got into this stuff to begin with because the monotony of client based web work will make you hate being a programmer. I'm having a blast and my game is not crashing, tests well, performs well, looks good on all devices so far and has no noticeable negative impact on any of my testing devices. I expected failure because I was being so drunkenly careless with my code, but to my surprise, it had no noticeable impact. I am now starting to question the need to be careful. Help me regain the ability to care! ... or explain why it's not a bad thing to not care. Secondary disclaimer: I am aware of the benefits of maintainability. For myself and others. Agreed. But it's not like someone happening across my inefficient int[] loop won't know what it does. As an experienced programmer those kinds of things are just clear on sight. I document the complex stuff for myself knowing I was drunk and will probably need a reminder. Those notes would clarify any confusion for someone who might ever gaze upon my ridiculous game - though the reality is that either I maintain it myself or it fades into time. I'm ok with that. But if it doesn't slow the device down, or crash, then crossing the t's and dotting the i's might actually require more time than it's worth.

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• Source Control and SQL Development &ndash; Part 3

  - by Ajarn Mark Caldwell

  In parts one and two of this series, I have been specifically focusing on the latest version of SQL Source Control by Red Gate Software.  But I have been doing source-controlled SQL development for years, long before this product was available, and well before Microsoft came out with Database Projects for Visual Studio.  “So, how does that work?” you may wonder.  Well, let me share some of the details of how we do it where I work… The key to this approach is that everything is done via Transact-SQL script files; either natively written T-SQL, or generated.  My preference is to write all my code by hand, which forces you to become better at your SQL syntax.  But if you really prefer to use the Management Studio GUI to make database changes, you can still do that, and then you use the Generate Scripts feature of the GUI to produce T-SQL scripts afterwards, and store those in your source control system.  You can generate scripts for things like stored procedures and views by right-clicking on the database in the Object Explorer, and Choosing Tasks, Generate Scripts (see figure 1 to the left).  You can also do that for the CREATE scripts for tables, but that does not work when you have a table that is already in production, and you need to make just a simple change, such as adding a new column or index.  In this case, you can use the GUI to make the table changes, and then instead of clicking the Save button, click the Generate Change Script button (). Then, once you have saved the change script, go ahead and execute it on your development database to actually make the change.  I believe that it is important to actually execute the script rather than just click the Save button because this is your first test that your change script is working and you didn’t somehow lose a portion of the change. As you can imagine, all this generating of scripts can get tedious and tempting to skip entirely, so again, I would encourage you to just get in the habit of writing your own Transact-SQL code, and then it is just a matter of remembering to save your work, just like you are in the habit of saving changes to a Word or Excel document before you exit the program. So, now that you have all of these script files, what do you do with them?  Well, we organize ours into folders labeled ChangeScripts, Functions, Views, and StoredProcedures, and those folders are loaded into our source control system.  ChangeScripts contains all of the table and index changes, and anything else that is basically a one-time-only execution.  Of course you want to write your scripts with qualifying logic so that if a script were accidentally run more than once in a database, it would not crash nor corrupt anything; but these scripts are really intended to be run only once in a database. Once you have your initial set of scripts loaded into source control, then making changes, such as altering a stored procedure becomes a simple matter of checking out your CREATE PROCEDURE* script, editing it in SSMS, saving the change, executing the script in order to effect the change in your database, and then checking the script back in to source control.  Of course, this is where the lack of integration for source control systems within SSMS becomes an irritation, because this means that in addition to SSMS, I also have my source control client application running to do the check-out and check-in.  And when you have 800+ procedures like we do, that can be quite tedious to locate the procedure I want to change in source control, check it out, then locate the script file in my working folder, open it in SSMS, do the change, save it, and the go back to source control to check in.  Granted, it is not nearly as burdensome as, say, losing your source code and having to rebuild it from memory, or losing the audit trail that good source control systems provide.  It is worth the effort, and this is how I have been doing development for the last several years. Remember that everything that the SQL Server Management Studio does in modifying your database can also be done in plain Transact-SQL code, and this is what you are storing.  And now I have shown you how you can do it all without spending any extra money.  You already have source control, or can get free, open-source source control systems (almost seems like an oxymoron, doesn’t it) and of course Management Studio is free with your SQL Server database engine software. So, whether you spend the money on tools to make it easier, or not, you now have no excuse for not using source control with your SQL development. * In our current model, the scripts for stored procedures and similar database objects are written with an IF EXISTS…DROP… at the top, followed by the CREATE PROCEDURE… section, and that followed by a section that assigns permissions.  This allows me to run the same script regardless of whether the procedure previously existed in the database.  If the script was only an ALTER PROCEDURE, then it would fail the first time that procedure was deployed to a database, unless you wrote other code to stub it if it did not exist.  There are a few different ways you could organize your scripts for deployment, each with its own trade-offs, but I think it is absolutely critical that whichever way you organize things, you ensure that the same script is run throughout the deployment cycle, and do not allow customizations to creep in between TEST and PROD.  If you do, then you have broken the integrity of your deployment process because what you deployed to PROD was not exactly the same as what was tested in TEST, so you effectively have now released untested code into PROD.

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• Subterranean IL: Generics and array covariance

  - by Simon Cooper

  Arrays in .NET are curious beasts. They are the only built-in collection types in the CLR, and SZ-arrays (single dimension, zero-indexed) have their own commands and IL syntax. One of their stranger properties is they have a kind of built-in covariance long before generic variance was added in .NET 4. However, this causes a subtle but important problem with generics. First of all, we need to briefly recap on array covariance. SZ-array covariance To demonstrate, I'll tweak the classes I introduced in my previous posts: public class IncrementableClass { public int Value; public virtual void Increment(int incrementBy) { Value += incrementBy; } } public class IncrementableClassx2 : IncrementableClass { public override void Increment(int incrementBy) { base.Increment(incrementBy); base.Increment(incrementBy); } } In the CLR, SZ-arrays of reference types are implicitly convertible to arrays of the element's supertypes, all the way up to object (note that this does not apply to value types). That is, an instance of IncrementableClassx2[] can be used wherever a IncrementableClass[] or object[] is required. When an SZ-array could be used in this fashion, a run-time type check is performed when you try to insert an object into the array to make sure you're not trying to insert an instance of IncrementableClass into an IncrementableClassx2[]. This check means that the following code will compile fine but will fail at run-time: IncrementableClass[] array = new IncrementableClassx2[1]; array[0] = new IncrementableClass(); // throws ArrayTypeMismatchException These checks are enforced by the various stelem* and ldelem* il instructions in such a way as to ensure you can't insert a IncrementableClass into a IncrementableClassx2[]. For the rest of this post, however, I'm going to concentrate on the ldelema instruction. ldelema This instruction pops the array index (int32) and array reference (O) off the stack, and pushes a pointer (&) to the corresponding array element. However, unlike the ldelem instruction, the instruction's type argument must match the run-time array type exactly. This is because, once you've got a managed pointer, you can use that pointer to both load and store values in that array element using the ldind* and stind* (load/store indirect) instructions. As the same pointer can be used for both input and output to the array, the type argument to ldelema must be invariant. At the time, this was a perfectly reasonable restriction, and maintained array type-safety within managed code. However, along came generics, and with it the constrained callvirt instruction. So, what happens when we combine array covariance and constrained callvirt? .method public static void CallIncrementArrayValue() { // IncrementableClassx2[] arr = new IncrementableClassx2[1] ldc.i4.1 newarr IncrementableClassx2 // arr[0] = new IncrementableClassx2(); dup newobj instance void IncrementableClassx2::.ctor() ldc.i4.0 stelem.ref // IncrementArrayValue<IncrementableClass>(arr, 0) // here, we're treating an IncrementableClassx2[] as IncrementableClass[] dup ldc.i4.0 call void IncrementArrayValue<class IncrementableClass>(!!0[],int32) // ... ret } .method public static void IncrementArrayValue<(IncrementableClass) T>( !!T[] arr, int32 index) { // arr[index].Increment(1) ldarg.0 ldarg.1 ldelema !!T ldc.i4.1 constrained. !!T callvirt instance void IIncrementable::Increment(int32) ret } And the result: Unhandled Exception: System.ArrayTypeMismatchException: Attempted to access an element as a type incompatible with the array. at IncrementArrayValue[T](T[] arr, Int32 index) at CallIncrementArrayValue() Hmm. We're instantiating the generic method as IncrementArrayValue<IncrementableClass>, but passing in an IncrementableClassx2[], hence the ldelema instruction is failing as it's expecting an IncrementableClass[]. On features and feature conflicts What we've got here is a conflict between existing behaviour (ldelema ensuring type safety on covariant arrays) and new behaviour (managed pointers to object references used for every constrained callvirt on generic type instances). And, although this is an edge case, there is no general workaround. The generic method could be hidden behind several layers of assemblies, wrappers and interfaces that make it a requirement to use array covariance when calling the generic method. Furthermore, this will only fail at runtime, whereas compile-time safety is what generics were designed for! The solution is the readonly. prefix instruction. This modifies the ldelema instruction to ignore the exact type check for arrays of reference types, and so it lets us take the address of array elements using a covariant type to the actual run-time type of the array: .method public static void IncrementArrayValue<(IncrementableClass) T>( !!T[] arr, int32 index) { // arr[index].Increment(1) ldarg.0 ldarg.1 readonly. ldelema !!T ldc.i4.1 constrained. !!T callvirt instance void IIncrementable::Increment(int32) ret } But what about type safety? In return for ignoring the type check, the resulting controlled mutability pointer can only be used in the following situations: As the object parameter to ldfld, ldflda, stfld, call and constrained callvirt instructions As the pointer parameter to ldobj or ldind* As the source parameter to cpobj In other words, the only operations allowed are those that read from the pointer; stind* and similar that alter the pointer itself are banned. This ensures that the array element we're pointing to won't be changed to anything untoward, and so type safety within the array is maintained. This is a typical example of the maxim that whenever you add a feature to a program, you have to consider how that feature interacts with every single one of the existing features. Although an edge case, the readonly. prefix instruction ensures that generics and array covariance work together and that compile-time type safety is maintained. Tune in next time for a look at the .ctor generic type constraint, and what it means.

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• Best Method For Evaluating Existing Software or New Software

  How many of us have been faced with having to decide on an off-the-self or a custom built component, application, or solution to integrate in to an existing system or to be the core foundation of a new system? What is the best method for evaluating existing software or new software still in the design phase? One of the industry preferred methodologies to use is the Active Reviews for Intermediate Designs (ARID) evaluation process.  ARID is a hybrid mixture of the Active Design Review (ADR) methodology and the Architectural Tradeoff Analysis Method (ATAM). So what is ARID? ARD’s main goal is to ensure quality, detailed designs in software. One way in which it does this is by empowering reviewers by assigning generic open ended survey questions. This approach attempts to remove the possibility for allowing the standard answers such as “Yes” or “No”. The ADR process ignores the “Yes”/”No” questions due to the fact that they can be leading based on how the question is asked. Additionally these questions tend to receive less thought in comparison to more open ended questions. Common Active Design Review Questions What possible exceptions can occur in this component, application, or solution? How should exceptions be handled in this component, application, or solution? Where should exceptions be handled in this component, application, or solution? How should the component, application, or solution flow based on the design? What is the maximum execution time for every component, application, or solution? What environments can this component, application, or solution? What data dependencies does this component, application, or solution have? What kind of data does this component, application, or solution require? Ok, now I know what ARID is, how can I apply? Let’s imagine that your organization is going to purchase an off-the-shelf (OTS) solution for its customer-relationship management software. What process would we use to ensure that the correct purchase is made? If we use ARID, then we will have a series of 9 steps broken up by 2 phases in order to ensure that the correct OTS solution is purchases. Phase 1 Identify the Reviewers Prepare the Design Briefing Prepare the Seed Scenarios Prepare the Materials When identifying reviewers for a design it is preferred that they be pulled from a candidate pool comprised of developers that are going to implement the design. The believe is that developers actually implementing the design will have more a vested interest in ensuring that the design is correct prior to the start of code. Design debriefing consist of a summary of the design, examples of the design solving real world examples put in to use and should be no longer than two hours typically. The primary goal of this briefing is to adequately summarize the design so that the review members could actually implement the design. In the example of purchasing an OTS product I would attempt to review my briefing prior to its distribution with the review facilitator to ensure that nothing was excluded that should have not been. This practice will also allow me to test the length of the briefing to ensure that can be delivered in an appropriate about of time. Seed Scenarios are designed to illustrate conceptualized scenarios when applied with a set of sample data. These scenarios can then be used by the reviewers in the actual evaluation of the software, All materials needed for the evaluation should be prepared ahead of time so that they can be reviewed prior to and during the meeting. Materials Included: Presentation Seed Scenarios Review Agenda Phase 2 Present ARID Present Design Brainstorm and prioritize scenarios Apply scenarios Summarize Prior to the start of any ARID review meeting the Facilitator should define the remaining steps of ARID so that all the participants know exactly what they are doing prior to the start of the review process. Once the ARID rules have been laid out, then the lead designer presents an overview of the design which typically takes about two hours. During this time no questions about the design or rational are allowed to be asked by the review panel as a standard, but they are written down for use latter in the process. After the presentation the list of compiled questions is then summarized and sent back to the lead designer as areas that need to be addressed further. In the example of purchasing an OTS product issues could arise regarding security, the implementation needed or even if this is this the correct product to solve the needed solution. After the Design presentation a brainstorming and prioritize scenarios process begins by reducing the seed scenarios down to just the highest priority scenarios.  These will then be used to test the design for suitability. Once the selected scenarios have been defined the reviewers apply the examples provided in the presentation to the scenarios. The intended output of this process is to provide code or pseudo code that makes use of the examples provided while solving the selected seed scenarios. As a standard rule, the designers of the systems are not allowed to help the review board unless they all become stuck. When this occurs it is documented and along with the reason why the designer needed to help the review panel back on track. Once all of the scenarios have been completed the review facilitator reviews with the group issues that arise during the process. Then the reviewers will be polled as to efficacy of the review experience. References: Clements, Paul., Kazman, Rick., Klien, Mark. (2002). Evaluating Software Architectures: Methods and Case Studies Indianapolis, IN: Addison-Wesley

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• Implement Tree/Details With Taskflow Regions Using EJB

  - by Deepak Siddappa

  This article describes on Display Tree/Details using taskflow regions.Use Case DescriptionLet us take scenario where we need to display Tree/Details, left region contains category hierarchy with items listed in a tree structure (ex:- Region-Countries-Locations-Departments in tree format) and right region contains the Employees list.In detail, Here User may drills down through categories using a tree until Employees are listed. Clicking the tree node name displays Employee list in the adjacent pane related to particular tree node. Implementation StepsThe script for creating the tables and inserting the data required for this application CreateSchema.sql Lets create a Java EE Web Application with Entities based on Regions, Countries, Locations, Departments and Employees table. Create a Stateless Session Bean and data control for the Stateless Session Bean. Add the below code to the session bean and expose the method in local/remote interface and generate a data control for that.Note:- Here in the below code "em" is a EntityManager. public List<Employees> empFilteredByTreeNode(String treeNodeType, String paramValue) { String queryString = null; try { if (treeNodeType == "null") { queryString = "select * from Employees emp ORDER BY emp.employee_id ASC"; } else if (Pattern.matches("[a-zA-Z]+[_]+[a-zA-Z]+[_]+[[0-9]+]+", treeNodeType)) { queryString = "select * from employees emp INNER JOIN departments dept\n" + "ON emp.department_id = dept.department_id JOIN locations loc\n" + "ON dept.location_id = loc.location_id JOIN countries cont\n" + "ON loc.country_id = cont.country_id JOIN regions reg\n" + "ON cont.region_id = reg.region_id and reg.region_name = '" + paramValue + "' ORDER BY emp.employee_id ASC"; } else if (treeNodeType.contains("regionsFindAll_bc_countriesList_1")) { queryString = "select * from employees emp INNER JOIN departments dept \n" + "ON emp.department_id = dept.department_id JOIN locations loc \n" + "ON dept.location_id = loc.location_id JOIN countries cont \n" + "ON loc.country_id = cont.country_id and cont.country_name = '" + paramValue + "' ORDER BY emp.employee_id ASC"; } else if (treeNodeType.contains("regionsFindAll_bc_locationsList_1")) { queryString = "select * from employees emp INNER JOIN departments dept ON emp.department_id = dept.department_id JOIN locations loc ON dept.location_id = loc.location_id and loc.city = '" + paramValue + "' ORDER BY emp.employee_id ASC"; } else if (treeNodeType.trim().contains("regionsFindAll_bc_departmentsList_1")) { queryString = "select * from Employees emp INNER JOIN Departments dept ON emp.DEPARTMENT_ID = dept.DEPARTMENT_ID and dept.DEPARTMENT_NAME = '" + paramValue + "'"; } } catch (NullPointerException e) { System.out.println(e.getMessage()); } return em.createNativeQuery(queryString, Employees.class).getResultList(); } In the ViewController project, create two ADF taskflow with page Fragments and name them as FirstTaskflow and SecondTaskflow respectively. Open FirstTaskflow,from component palette drop view(Page Fragment) name it as TreeList.jsff. Open SeconfTaskflow, from component palette drop view(Page Fragment) name it as EmpList.jsff and create two paramters in its overview parameters tab as shown in below image. Open TreeList.jsff , from data control palette drop regionsFindAll->Tree as ADF Tree. In Edit Tree Binding dialog, for Tree Level Rules select the display attributes as follows:-model.Regions - regionNamemodel.Countries - countryNamemodel.Locations - citymodel.Departments - departmentName In structure panel, click on af:Tree - t1 and select selectionListener with edit property. Create a "TreeBean" managed bean with scope as "session" as shown in below Image. Create new method as getTreeNodeSelectedValue and click ok. Open TreeBean managed bean and add the below code: private String treeNodeType; private String paramValue; public void getTreeNodeSelectedValue(SelectionEvent selectionEvent) { RichTree tree = (RichTree)selectionEvent.getSource(); RowKeySet addedSet = selectionEvent.getAddedSet(); Iterator i = addedSet.iterator(); TreeModel model = (TreeModel)tree.getValue(); model.setRowKey(i.next()); JUCtrlHierNodeBinding node = (JUCtrlHierNodeBinding)tree.getRowData(); //oracle.jbo.Row Row rw = node.getRow(); Object selectedTreeNode = node.getAttribute(0); Object treeListType = node.getBindings(); String treeNodeType = treeListType.toString(); this.setParamValue(selectedTreeNode.toString()); this.setTreeNodeType(treeNodeType); } public void setTreeNodeType(String treeNodeType) { this.treeNodeType = treeNodeType; } public String getTreeNodeType() { return treeNodeType; } public void setParamValue(String paramValue) { this.paramValue = paramValue; } public String getParamValue() { return paramValue; }<br /> Open EmpList.jsff , from data control palette drop empFilteredByTreeNode->Employees->Table as ADF Read-only Table. After selecting the  Employees result set, in Edit Action Binding dialog window pass the pageFlowScope parameters as shown in below Image. In empList.jsff page, click Binding tab and click on Create Executable binding and select Invoke action and follow as shown in below image. Edit executeEmpFiltered invoke action properties and set the Refresh to ifNeeded, So when ever the page needs the method will be executed. Create Main.jspx page with page template as Oracle Three Column Layout. Drop FirstTaskflow as Region in start facet and drop SecondTaskflow as Region in center facet, Edit task Flow Binding dialog window pass the Input Paramters as shown in below Image. Run the Main.jspx, tree will be displayed in left region and emp details will displyaed on the right region. Click on the Americas in tree node, all emp related to the Americas related will be displayed. Click on Americas->United States of America->South San Francisco->Accounting, only employee belongs to the Accounting department will be displayed.

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• Application Development: Python or Java (or PHP)

  - by luckysmack

  I'm looking to get into application development, such as Facebook or Android apps and games. I am doing this for fun and to learn. Once my skills are to par I would like to have some side income from the apps, but I'm not banking on living off that (just so you know where I'm coming from and know what my end goals are). Currently I know and am familiar with PHP and frameworks such as cakephp and yii. However, I have been wanting to learn another language to broaden my horizons and to become a better developer. So I have narrowed it down to 2 languages. Python, and Java (I can already hear people cringing at the difference in the languages I have chosen, but I have some reasons). Python: closer to PHP that Java. Cross platformability. Also great as a general scripting language and has many file system level benefits that PHP does not. Cleaner syntax, readability, blah blah and the list goed on. Python will work great for cross platform apps and can be run on many OS's and is supported by Facebook for app development. But there is no support on Android (for full fledged apps). Java: a much stronger typed language, very robust community and corporate backing. Knowing Java is also good for personal marketability for enterprises, if you're into that. The main benefit here is that Java can write apps natively for Android and the apps can be ported for web versions to play on Facebook. So while I have seen many developers prefer Java over the two, Java has this significant advantage, where I can market my apps in both markets and in the future build more potential income. But like I said it is for fun. While money isn't the goal, it would still be nice. PHP: I'm putting this here because I know it already, and I'm sure a case could be made for it. It obviously works great for Facebook but like Python does not do so well on android. While it's mostly the realm of 'application development' that appeals to me, I do find Android apps fairly interesting and something that has a ton of potential to. But then again Facebook has a ton more users and the apps can also potentially be more immersive (desktop vs. mobile). So this is why I'm kinda stuck on what route to choose. Python for Facebook and web apps, with likely faster development to production times, or Java which can be developed for any of the platforms to make apps. Side note: I'm not really trying to get into 3D development, mostly 2D. And I also want to make an app with real-time play (websockets, etc). Someone mentioned node, js to me for that but Python seems to be more globally versatile for my goals. So, to anyone that does Facebook or Android development in either language: what do you suggest? Any input is valuable and I do appreciate it. And sorry for being long winded. EDIT: as mentioned in one of the answers, my primary goal is gaming. Although I do have some plans for non gaming apps such as general web based and desktop based ones. But gaming is my main goal with the possibility of income. EDIT: Another consideration could be Jython. Writing Python code which is converted into Java bytecode. This would allow the ability to do Android apps using Python. I could be wrong though, I'm still looking into it. Update 1-26-11: I recently acquired a new job which required I learn .NET using C#. Im sure some of you are cringing already but I really like the whole system and how it all works together between desktop and web development. But, as I am still interested in Python very much, and after some research I have decided I will learn Python as well as the IronPython implementation for .NET. But (again: I know...) since .NET is mostly a Windows thing and not as cross-compatible as I like, I will be learning Mono which is a cross platform implementation of .NET where I can use what I learn at work using C# and what I want to learn, Python/IronPython. So while learning and writing C#/.NET @ work I will be learning Python - Mono - Iron Python for what I want to do personally. And the benefit of them all being very closely related will help me out a lot, I think. What do you guys think? I almost feel like that should be another question, but there's not much of a question. Either way, you guys gave very helpful input.

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• Converting LINQ to Twitter to Twitter API v1.1

  - by Joe Mayo

  Twitter recently updated their API to v1.1 (Current status: API v1.1). Naturally, LINQ to Twitter  needed to be updated too. This blog post outlines the changes made to LINQ to Twitter during this conversion and highlights important features that LINQ to Twitter developers will want to know. Overall Impact Generally speaking, Twitter API v1.1 is semantically very much the same as it’s predecessor. The base URL changed and so did a few resource segments, but the resources themselves are still intact. The good news is that LINQ to Twitter has always shielded the developer from this plumbing, so the entities, types, and filters didn’t change much at all.  The following sections describe what did  change. Authentication In Twitter API v1.0 authentication was not required for some resources, such as user timelines and search. However, that’s all changed because *all* queries must be authenticated in Twitter API v1.1. LINQ to Twitter has various types of authorizers you can use, supporting whatever OAuth options are available via Twitter.  You can see the LINQ to Twitter documentation, Securing Your Applications, for more info on OAuth support. The New Search One of the larger changes to the API was Search. To be more specific, the Search entity now contains a List<Status>, named Statuses, to hold results.  Additionally, any meta-data associated with the search is now in a property named SearchMetaData. The change to the Search entity and responses is the big change, but the good news is that your Search query syntax doesn’t change. Different Rate Limits The issue of rate limits itself is contentious, but this discussion is focused on the coding experience and I’ll leave the politics to those who prefer to engage in that activity. What’s important here is that both headers and resources have changed. You should review Twitter’s Rate Limit documentation to understand what the changes mean.  A quick explanation is that rate limits are applied individually to each resource in 15 minute time intervals. In LINQ to Twitter these changes surface on the Help entity, via HelpType.RateLimits. The RateLimits query has a Resources filter where you can specify a comma-separated list of categories to return rate limit info for.  The results materialize in the RateLimits dictionary, keyed on category. The Help entity also has a RateLimitsAuthorizationContext, holding the Access Token for the user performing queries – and to whom the rate limits apply. In addition to the new RateLimits query, there are new RateLimit headers that appear in the query response, whose HTTP header name is of the form X-Rate-Limit… which is different from the previous header name. LINQ to Twitter surfaces these headers via the existing properties of the TwitterContext instance. For anyone who retrieved rate limit information via the Headers property of TwitterContext, you should be aware of the new header names.  I haven’t done anything with Feature rate limit properties yet, but they appear to no longer be available – this will require more follow-up. Error Handling Twitter API v1.1 has a new format for Error Codes & Responses. LINQ to Twitter wraps these messages in the TwitterQueryException, which has been updated appropriately. The Message property of TwitterQueryException now reflects the Twitter error message, when available. There’s also a new ErrorCode that’s populated with the message error code. Parameters Most parameters stayed the same, but one of interest is Include Entities (different from LINQ to Twitter data object entities). Entities are metadata hanging off tweets, that provide start/end position in the tweet and other information for mentions, urls, hash tags, and media. Entities used to not be included unless you specified you wanted them. Now, in v1.1, entities are included by default for all APIs that return a Status.  If you were always setting IncludeEntities to true, then you won’t see a change. However, be aware that you’ll now be receiving additional data in your response from Twitter, which will explain a sudden increase in bandwidth utilization. This might or might not  matter to you  depending on the requirements of your application, but you should be aware of it. Everything Else There might be small changes here and there that I haven’t mentioned, but these were the ones you should be most aware of.  Streams didn’t change, but Twitter will be deprecating username/password authentication on public streams, in favor of OAuth, so you’ll be seeing me make that change some time in the future.  Also, Twitter will continue to evolve the API and you can expect that LINQ to Twitter will change accordingly. Summary The big changes to Twitter API were Authentication, Search, Rate Limits, and Error Handling. All API calls must be authenticated. You’ll need to change your code to read Search results differently, but the query is much the same as you use now. There’s a new RateLimits API, one of the Help queries.  Also, the new error messages are integrated into TwitterQueryException. Besides these changes, I expect  most others to be small or affect a smaller percentage of developers.  You can get the latest version of LINQ to Twitter from NuGet or visit the LINQ to Twitter download page at CodePlex.com.   @JoeMayo

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• Scripting custom drawing in Delphi application with IF/THEN/ELSE statements?

  - by Jerry Dodge

  I'm building a Delphi application which displays a blueprint of a building, including doors, windows, wiring, lighting, outlets, switches, etc. I have implemented a very lightweight script of my own to call drawing commands to the canvas, which is loaded from a database. For example, one command is ELP 1110,1110,1290,1290,3,8388608 which draws an ellipse, parameters are 1110x1110 to 1290x1290 with pen width of 3 and the color 8388608 converted from an integer to a TColor. What I'm now doing is implementing objects with common drawing routines, and I'd like to use my scripting engine, but this calls for IF/THEN/ELSE statements and such. For example, when I'm drawing a light, if the light is turned on, I'd like to draw it yellow, but if it's off, I'd like to draw it gray. My current scripting engine has no recognition of such statements. It just accepts simple drawing commands which correspond with TCanvas methods. Here's the procedure I've developed (incomplete) for executing a drawing command on a canvas: function DrawCommand(const Cmd: String; var Canvas: TCanvas): Boolean; type TSingleArray = array of Single; var Br: TBrush; Pn: TPen; X: Integer; P: Integer; L: String; Inst: String; T: String; Nums: TSingleArray; begin Result:= False; Br:= Canvas.Brush; Pn:= Canvas.Pen; if Assigned(Canvas) then begin if Length(Cmd) > 5 then begin L:= UpperCase(Cmd); if Pos(' ', L)> 0 then begin Inst:= Copy(L, 1, Pos(' ', L) - 1); Delete(L, 1, Pos(' ', L)); L:= L + ','; SetLength(Nums, 0); X:= 0; while Pos(',', L) > 0 do begin P:= Pos(',', L); T:= Copy(L, 1, P - 1); Delete(L, 1, P); SetLength(Nums, X + 1); Nums[X]:= StrToFloatDef(T, 0); Inc(X); end; Br.Style:= bsClear; Pn.Style:= psSolid; Pn.Color:= clBlack; if Inst = 'LIN' then begin Pn.Width:= Trunc(Nums[4]); if Length(Nums) > 5 then begin Br.Style:= bsSolid; Br.Color:= Trunc(Nums[5]); end; Canvas.MoveTo(Trunc(Nums[0]), Trunc(Nums[1])); Canvas.LineTo(Trunc(Nums[2]), Trunc(Nums[3])); Result:= True; end else if Inst = 'ELP' then begin Pn.Width:= Trunc(Nums[4]); if Length(Nums) > 5 then begin Br.Style:= bsSolid; Br.Color:= Trunc(Nums[5]); end; Canvas.Ellipse(Trunc(Nums[0]),Trunc(Nums[1]),Trunc(Nums[2]),Trunc(Nums[3])); Result:= True; end else if Inst = 'ARC' then begin Pn.Width:= Trunc(Nums[8]); Canvas.Arc(Trunc(Nums[0]),Trunc(Nums[1]),Trunc(Nums[2]),Trunc(Nums[3]), Trunc(Nums[4]),Trunc(Nums[5]),Trunc(Nums[6]),Trunc(Nums[7])); Result:= True; end else if Inst = 'TXT' then begin Canvas.Font.Size:= Trunc(Nums[2]); Br.Style:= bsClear; Pn.Style:= psSolid; T:= Cmd; Delete(T, 1, Pos(' ', T)); Delete(T, 1, Pos(',', T)); Delete(T, 1, Pos(',', T)); Delete(T, 1, Pos(',', T)); Canvas.TextOut(Trunc(Nums[0]), Trunc(Nums[1]), T); Result:= True; end; end else begin //No space found, not a valid command end; end; end; end; What I'd like to know is what's a good lightweight third-party scripting engine I could use to accomplish this? I would hate to implement parsing of IF, THEN, ELSE, END, IFELSE, IFEND, and all those necessary commands. I need simply the ability to tell the scripting engine if certain properties meet certain conditions, it needs to draw the object a certain way. The light example above is only one scenario, but the same solution needs to also be applicable to other scenarios, such as a door being open or closed, locked or unlocked, and draw it a different way accordingly. This needs to be implemented in the object script drawing level. I can't hard-code any of these scripting/drawing rules, the drawing needs to be controlled based on the current state of the object, and I may also wish to draw a light a certain shade or darkness depending on how dimmed the light is.

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• Custom Configuration Section Handlers

  Most .NET developers who need to store something in configuration tend to use appSettings for this purpose, in my experience.  More recently, the framework itself has helped things by adding the <connectionStrings /> section so at least these are in their own section and not adding to the appSettings clutter that pollutes most apps.  I recommend avoiding appSettings for several reasons.  In addition to those listed there, I would add that strong typing and validation are additional reasons to go the custom configuration section route. For my ASP.NET Tips and Tricks talk, I use the following example, which is a simple DemoSettings class that includes two fields.  The first is an integer representing how many attendees there are present for the talk, and the second is the title of the talk.  The setup in web.config is as follows: <configSections> <section name="DemoSettings" type="ASPNETTipsAndTricks.Code.DemoSettings" /> </configSections>   <DemoSettings sessionAttendees="100" title="ASP.NET Tips and Tricks DevConnections Spring 2010" /> Referencing the values in code is strongly typed and straightforward.  Here I have a page that exposes two properties which internally get their values from the configuration section handler: public partial class CustomConfig1 : System.Web.UI.Page { public string SessionTitle { get { return DemoSettings.Settings.Title; } } public int SessionAttendees { get { return DemoSettings.Settings.SessionAttendees; } } } Note that the settings are only read from the config file once after that they are cached so there is no need to be concerned about excessive file access. Now weve seen how to set it up on the config file and how to refer to the settings in code.  All that remains is to see the file itself: public class DemoSettings : ConfigurationSection { private static DemoSettings settings = ConfigurationManager.GetSection("DemoSettings") as DemoSettings; public static DemoSettings Settings{ get { return settings;} }   [ConfigurationProperty("sessionAttendees" , DefaultValue = 200 , IsRequired = false)] [IntegerValidator(MinValue = 1 , MaxValue = 10000)] public int SessionAttendees { get { return (int)this["sessionAttendees"]; } set { this["sessionAttendees"] = value; } }   [ConfigurationProperty("title" , IsRequired = true)] [StringValidator(InvalidCharacters = "~!@#$%^&*()[]{}/;\"|\\")] public string Title { get { return (string)this["title"]; } set { this["title"] = value; }   } } The class is pretty straightforward, but there are some important components to note.  First, it must inherit from System.Configuration.ConfigurationSection.  Next, as a convention I like to have a static settings member that is responsible for pulling out the section when the class is first referenced, and further to expose this collection via a static readonly property, Settings.  Note that the types of both of these are the type of my class, DemoSettings. The properties of the class, SessionAttendees and Title, should map to the attributes of the config element in the XML file.  The [ConfigurationProperty] attribute allows you to map the attribute name to the property name (thus using both XML standard naming conventions and C# naming conventions).  In addition, you can specify a default value to use if nothing is specified in the config file, and whether or not the setting must be provided (IsRequired).  If it is required, then it doesnt make sense to include a default value. Beyond defaults and required, you can specify more advanced validation rules for the configuration values using additional C# attributes, such as [IntegerValidator] and [StringValidator].  Using these, you can declaratively specify that your configuration values be in a given range, or omit certain forbidden characters, for instance.  Of course you can write your own custom validation attributes, and there are others specified in System.Configuration. Individual sections can also be loaded from separate files, using syntax like this: <DemoSettings configSource="demosettings.config" /> Summary Using a custom configuration section handler is not hard.  If your application or component requires configuration, I recommend creating a custom configuration handler dedicated to your app or component.  Doing so will reduce the clutter in appSettings, will provide you with strong typing and validation, and will make it much easier for other developers or system administrators to locate and understand the various configuration values that are necessary for a given application. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• AppHarbor - Azure Done Right AKA Heroku for .NET

  - by Robz / Fervent Coder

  Easy and Instant deployments and instant scale for .NET? Awhile back a few of us were looking at Ruby Gems as the answer to package management for .NET. The gems platform supported the concept of DLLs as packages although some changes would have needed to happen to have long term use for the entire community. From that we formed a partnership with some folks at Microsoft to make v2 into something that would meet wider adoption across the community, which people now call NuGet. So now we have the concept of package management. What comes next? Heroku Instant deployments and instant scaling. Stupid simple API. This is Heroku. It doesn’t sound like much, but when you think of how fast you can go from an idea to having someone else tinker with it, you can start to see its power. In literally seconds you can be looking at your rails application deployed and online. Then when you are ready to scale, you can do that. This is power. Some may call this “cloud-computing” or PaaS (Platform as a Service). I first ran into Heroku back in July when I met Nick of RubyGems.org. At the time there was no alternative in the .NET-o-sphere. I don’t count Windows Azure, mostly because it is not simple and I don’t believe there is a free version. Heroku itself would not lend itself well to .NET due to the nature of platforms and each language’s specific needs (solution stack).  So I tucked the idea in the back of my head and moved on. AppHarbor Enters The Scene I’m not sure when I first heard about AppHarbor as a possible .NET version of Heroku. It may have been in November, but I didn’t actually try it until January. I was instantly hooked. AppHarbor is awesome! It still has a ways to go to be considered Heroku for .NET, but it already has a growing community. I created a video series (at the bottom of this post) that really highlights how fast you can get a product onto the web and really shows the power and simplicity of AppHarbor. Deploying is as simple as a git/hg push to appharbor. From there they build your code, run any unit tests you have and deploy it if everything succeeds. The screen on the right shows a simple and elegant UI to getting things done. The folks at AppHarbor graciously gave me a limited number of invites to hand out. If you are itching to try AppHarbor then navigate to: https://appharbor.com/account/new?inviteCode=ferventcoder  After playing with it, send feedback if you want more features. Go vote up two features I want that will make it more like Heroku. Disclaimer: I am in no way affiliated with AppHarbor and have not received any funds or favors from anyone at AppHarbor. I just think it is awesome and I want others to know about it. From Zero To Deployed in 15 Minutes (Or Less) Now I have a challenge for you. I created a video series showing how fast I could go from nothing to a deployed application. It could have been from Zero to Deployed in Less than 5 minutes, but I wanted to show you the tools a little more and give you an opportunity to beat my time. And that’s the challenge. Beat my time and show it in a video response. The video series is below (at least one of the videos has to be watched on YouTube). The person with the best time by March 15th @ 11:59PM CST will receive a prize. Ground rules: .NET Application with a valid database connection Start from Zero Deployed with AppHarbor or an alternative A timer displayed in the video that runs during the entire process Video response published on YouTube or acceptable alternative Video(s) must be published by March 15th at 11:59PM CST. Either post the link here as a comment or on YouTube as a response (also by 11:59PM CST March 15th) From Zero To Deployed In 15 Minutes (Or Less) Part 1 From Zero To Deployed In 15 Minutes (Or Less) Part 2 From Zero To Deployed In 15 Minutes (Or Less) Part 3

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• About Solaris 11 and UltraSPARC II/III/IV/IV+

  - by nospam(at)example.com (Joerg Moellenkamp)

  I know that I will get the usual amount of comments like "Oh, Jörg ? you can't be negative about Oracle" for this article. However as usual I want to explain the logic behind my reasoning. Yes ? I know that there is a lot of UltraSPARC III, IV and IV+ gear out there. But there are some very basic questions: Does your application you are currently running on this gear stops running just because you can't run Solaris 11 on it? What is the need to upgrade a system already in production to Solaris 11? I have the impression, that some people think that the systems get useless in the moment Oracle releases Solaris 11. I know that Sun sold UltraSPARC IV+ systems until 2009. The Sun SF490 introduced 2004 for example, that was a Sun SF480 with UltraSPARC IV and later with UltraSPARC IV+. And yes, Sun made some speedbumps. At that time the systems of the UltraSPARC III to IV+ generations were supported on Solaris 8, on Solaris 9 and on Solaris 10. However from my perspective we sold them to customers, which weren't able to migrate to Solaris 10 because they used applications not supported on Solaris 9 or who just didn't wanted to migrate to Solaris 10. Believe it or not ? I personally know two customers that migrated core systems to Solaris 10 in ? well 2008/9. This was especially true when the M3000 was announced in 2008 when it closed the darned single socket gap. It may be different at you site, however that's what I remember about that time when talking with customers. At first: Just because there is no Solaris 11 for UltraSPARC III, IV and IV+, it doesn't mean that Solaris 10 will go away anytime soon. I just want to point you to "Expect Lifetime Support - Hardware and Operating Systems". It states about Premier Support:Maintenance and software upgrades are included for Oracle operating systems and Oracle VM for a minimum of eight years from the general availability date.GA for Solaris 10 was in 2005. Plus 8 years ? 2013 ? at minimum. Then you can still opt for 3 years of "Extended Support" ? 2016 ? at minimum. 2016 your systems purchased in 2009 are 7 years old. Even on systems purchased at the very end of the lifetime of that system generation. That are the rules as written in the linked document. I said minimum The actual dates are even further in the future: Premier Support for Solaris 10 ends in 2015, Extended support ends 2018. Sustaining support ? indefinite. You will find this in the document "Oracle Lifetime Support Policy: Oracle Hardware and Operating Systems".So I don't understand when some people write, that Oracle is less protective about hardware investments than Sun. And for hardware it's the same as with Sun: Service 5 years after EOL as part of Premier Support. I would like to write about a different perspective as well: I have to be a little cautious here, because this is going in the roadmap area, so I will mention the public sources here: John Fowler told last year that we have to expect at at least 3x the single thread performance of T3 for T4. We have 8 cores in T4, as stated by Rick Hetherington. Let's assume for a moment that a T4 core will have the performance of a UltraSPARC core (just to simplify math and not to disclosing anything about the performance, all existing SPARC cores are considered equal). So given this pieces of information, you could consolidate 8 V215, 4 or 8 V245, 2 full blown V445,2 full blown 490, 2 full blown M3000 on a single T4 SPARC processor. The Fowler roadmap prezo talked about 4-socket systems with T4. So 32 V215, 16 to 8 V245, 8 fullblown V445, 8 full blown V490, 8 full blown M3000 in a system image. I think you get the idea. That said, most of the systems we are talking about have already amortized and perhaps it's just time to invest in new systems to yield other advantages like reduced space consumptions, like reduced power consumption, like some of the neat features sun4v gives you, and yes ? reduced number of processor licenses for Oracle and less money for Oracle HW/SW support. As much as I dislike it myself that my own UltraSPARC III and UltraSPARC II based systems won't run on Solaris 11 (and I have quite a few of them in my personal lab), I really think that the impact on production environments will be much less than most people think now. By the way: The reason for this move is a quite significant new feature. I will tell you that it was this feature, when it's out. I assume, telling just a word more could lead to much more time to blog.

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• yield – Just yet another sexy c# keyword?

  - by George Mamaladze

  yield (see NSDN c# reference) operator came I guess with .NET 2.0 and I my feeling is that it’s not as wide used as it could (or should) be.   I am not going to talk here about necessarity and advantages of using iterator pattern when accessing custom sequences (just google it).   Let’s look at it from the clean code point of view. Let's see if it really helps us to keep our code understandable, reusable and testable.   Let’s say we want to iterate a tree and do something with it’s nodes, for instance calculate a sum of their values. So the most elegant way would be to build a recursive method performing a classic depth traversal returning the sum.           private int CalculateTreeSum(Node top)         {             int sumOfChildNodes = 0;             foreach (Node childNode in top.ChildNodes)             {                 sumOfChildNodes += CalculateTreeSum(childNode);             }             return top.Value + sumOfChildNodes;         }     “Do One Thing” Nevertheless it violates one of the most important rules “Do One Thing”. Our  method CalculateTreeSum does two things at the same time. It travels inside the tree and performs some computation – in this case calculates sum. Doing two things in one method is definitely a bad thing because of several reasons: ·          Understandability: Readability / refactoring ·          Reuseability: when overriding - no chance to override computation without copying iteration code and vice versa. ·          Testability: you are not able to test computation without constructing the tree and you are not able to test correctness of tree iteration.   I want to spend some more words on this last issue. How do you test the method CalculateTreeSum when it contains two in one: computation & iteration? The only chance is to construct a test tree and assert the result of the method call, in our case the sum against our expectation. And if the test fails you do not know wether was the computation algorithm wrong or was that the iteration? At the end to top it all off I tell you: according to Murphy’s Law the iteration will have a bug as well as the calculation. Both bugs in a combination will cause the sum to be accidentally exactly the same you expect and the test will PASS. J   Ok let’s use yield! That’s why it is generally a very good idea not to mix but isolate “things”. Ok let’s use yield!           private int CalculateTreeSumClean(Node top)         {             IEnumerable<Node> treeNodes = GetTreeNodes(top);             return CalculateSum(treeNodes);         }             private int CalculateSum(IEnumerable<Node> nodes)         {             int sumOfNodes = 0;             foreach (Node node in nodes)             {                 sumOfNodes += node.Value;             }             return sumOfNodes;         }           private IEnumerable<Node> GetTreeNodes(Node top)         {             yield return top;             foreach (Node childNode in top.ChildNodes)             {                 foreach (Node currentNode in GetTreeNodes(childNode))                 {                     yield return currentNode;                 }             }         }   Two methods does not know anything about each other. One contains calculation logic another jut the iteration logic. You can relpace the tree iteration algorithm from depth traversal to breath trevaersal or use stack or visitor pattern instead of recursion. This will not influence your calculation logic. And vice versa you can relace the sum with product or do whatever you want with node values, the calculateion algorithm is not aware of beeng working on some tree or graph.  How about not using yield? Now let’s ask the question – what if we do not have yield operator? The brief look at the generated code gives us an answer. The compiler generates a 150 lines long class to implement the iteration logic.       [CompilerGenerated]     private sealed class <GetTreeNodes>d__0 : IEnumerable<Node>, IEnumerable, IEnumerator<Node>, IEnumerator, IDisposable     {         ...        150 Lines of generated code        ...     }   Often we compromise code readability, cleanness, testability, etc. – to reduce number of classes, code lines, keystrokes and mouse clicks. This is the human nature - we are lazy. Knowing and using such a sexy construct like yield, allows us to be lazy, write very few lines of code and at the same time stay clean and do one thing in a method. That's why I generally welcome using staff like that.   Note: The above used recursive depth traversal algorithm is possibly the compact one but not the best one from the performance and memory utilization point of view. It was taken to emphasize on other primary aspects of this post.

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• BizTalk: Sample: Context routing and Throttling with orchestration

  - by Leonid Ganeline

  The sample demonstrates using orchestration for throttling and using context routing. Usually throttling is implemented on the host level (in BizTalk 2010 we can also using the host instance level throttling). Here is demonstrated the throttling with orchestration convoy that slows down message flow from some customers. Sample implements sort of quality service agreement layer for different kind of customers. The sample demonstrates the context routing between orchestrations. It has several advantages over the content routing. For example, we don’t have to create the property schema and promote properties on the schemas; we don’t have to change the message content to change routing. Use case:  The BizTalk application has a main processing orchestration that process all input messages. The application usually works as an OLTP application. Input messages came in random order without peaks, typical scenario for the on-line users. But sometimes the big data batch payloads come. These batches overload processing orchestrations. All processes, activated by on-line users after the payload, come to the same queue and are processed only after the payload. Result is on-line users can see significant delay in processing. It can be minutes or hours, depending of the batch size. Requirements: On-line user’s processing should work without delays. Big batches cannot disturb on-line users. There should be higher priority for the on-line users and the lower priority for the batches. Design: Decision is to divide the message flow in two branches, one for on-line users and second for batches. Branch with batches provides messages to the processing line with low priority, and the on-line user’s branch – with high priority. All messages are provided by hi-speed receive port. BTS.ReceivePortName context property is used for routing. The Router orchestration separates messages sent from on-line users and from the batch messages. But the Router does not use the BizTalk provided value of this property, the Router set up this value by itself. Router uses the content of the messages to decide if it is from on-line users or from batches. The message context property the BTS.ReceivePortName is changed respectively, its value works as a recipient address, as the “To” address for the next recipient orchestrations. Those next orchestrations are the BatchBottleneck and the MainProcess orchestrations. Messages with context equal “ToBatch” are filtered up by the BatchBottleneck orchestration. It is a unified convoy orchestration and it throttles the message flow, delaying the message delivery to the MainProcess orchestration. The BatchBottleneck orchestration changes the message context to the “ToProcess” and sends messages one after another with small delay in between. Delay can be configured in the BizTalk config file as:                 <appSettings>                                 <add key="GLD_Tests_TwoWayRouting_BatchBottleneck_DelayMillisec" value="100"/>                 </appSettings>   Of course, messages with context equal “ToProcess” are filtered up by the MainProcess orchestration.   NOTES: Filters with string values: In Orchestrations (the first Receive shape in orchestration) use string values WITH quotes; in Send Ports use string values WITHOUT quotes. Filters on the Send Ports are dynamic; we can change them in run-time. Filters on the Orchestrations are static; we can change them only in design-time. To check the existence of the promoted property inside orchestration use the Expression shape with construction like this:       if (BTS.ReceivePortName exists myMessage) { …; } It is not possible in the Message Assignment shape because using the “if” statement inside Message Assignment is prohibited. Several predefined context properties can behave in specific way. Say MessageTracking.OriginatingMessage or XMLNORM.DocumentSpecName, they are required some internal rules should be applied to the format or usage of this properties. MessageTracking.* parameters require you have to use tracking and you can get unexpected run-time errors in some cases. My recommendation is - use very limited set of the predefined context properties. To “attach” the new promoted property to the message, we have to use correlation. The correlation type should include this property. [Here is a good explanation by Saravana ] The sample code is here [sorry, temporary trubles with CodePlex].

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• Use your own domain email and tired of SPAM? SPAMfighter FTW

  - by Dave Campbell

  I wouldn't post this if I hadn't tried it... and I paid for it myself, so don't anybody be thinking I'm reviewing something someone sent me! Long ago and far away I got very tired of local ISPs and 2nd phone lines and took the plunge and got hooked up to cable... yeah I know the 2nd phone line concept may be hard for everyone to understand, but that's how it was in 'the old days'. To avoid having to change email addresses all the time, I decided to buy a domain name, get minimal hosting, and use that for all email into the house. That way if I changed providers, all the email addresses wouldn't have to change. Of course, about a dozen domains later, I have LOTS of pop email addresses and even an exchange address to my client's server... times have changed. What also has changed is the fact that we get SPAM... 'back in the day' when I was a beta tester for the first ISP in Phoenix, someone tried sending an ad to all of us, and what he got in return for his trouble was a bunch of core dumps that locked up his email... if you don't know what a core dump is, ask your grandfather. But in today's world, we're all much more civilized than that, and as with many things, the criminals seem to have much more rights than we do, so we get inundated with email offering all sorts of wild schemes that you'd have to be brain-dead to accept, but yet... if people weren't accepting them, they'd stop sending them. I keep hoping that survival of the smartest would weed out the mental midgets that respond and then the jumk email stop, but that hasn't happened yet anymore than finding high-quality hearing aids at the checkout line of Safeway because of all the dimwits playing music too loud inside their car... but that's another whole topic and I digress. So what's the solution for all the spam? And I mean *all*... on that old personal email address, I am now getting over 150 spam messages a day! Yes I know that's why God invented the delete key, but I took it on as a challenge, and it's a matter of principle... why should I switch email addresses, or convert from [email protected] to something else, or have all my email filtered through some service just because some A-Hole somewhere has a site up trying to phish Ma & Pa Kettle (ask your grandfather about that too) out of their retirement money? Well... I got an email from my cousin the other day while I was writing yet another email rule, and there was a banner on the bottom of his email that said he was protected by SPAMfighter. SPAMfighter huh.... so I took a look at their site, and found yet one more of the supposed tools to help us. But... I read that they're a Microsoft Gold Partner... and that doesn't come lightly... so I took a gamble and here's what I found: I installed it, and had to do a couple things: 1) SPAMfighter stuffed the SPAMfighter folder into my client's exchange address... I deleted it, made a new SPAMfighter folder where I wanted it to go, then in the SPAMfighter Clients settings for Outlook, I told it to put all spam there. 2) It didn't seem to be doing anything. There's a ribbon button that you can select "Block", and I did that, wondering if I was 'training' it, but it wasn't picking up duplicates 3) I sent email to support, and wrote a post on the forum (not to self: reply to that post). By the time the folks from the home office responded, it was the next day, and first up, SPAMfighter knocked down everything that came through when Outlook opend... two thumbs up! I disabled my 'garbage collection' rule from Outlook, and told Outlook not to use the junk folder thinking it was interfering. 4) Day 2 seemed to go about like Day 1... but I hung in there. 5) Day 3 is now a whole new day... I had left Outlook open and hadn't looked at the PC since sometime late yesterday afternoon, and when I looked this morning, *every bit* of spam was in the SPAMfighter folder!! I'm a new paying customer After watching SPAMfighter work this morning, I've purchased a 1-year license, and I now can sit and watch as emails come in and disappear from my inbox into the SPAMfighter folder. No more continual tweaking of the rules. I've got SPAMfighter set to 'Very Hard' filtering... personally I'd rather pull the few real emails out of the SPAMfighter folder than pull spam out of the real folders. Yes this is simply another way of using the delete key, but you know what? ... it feels good :) Here's a screenshot of the stats after just about 48 hours of being onboard: Note that all the ones blocked by me were during Day 1 and 2... I've blocked none today, and everything is blocked. Stay in the 'Light!

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• Vendors: Partners or Salespeople?

  - by BuckWoody

  I got a great e-mail from a friend that asked about how he could foster a better relationship with his vendors. So many times when you work with a vendor it’s more of a used-car sales experience than a partnership – but you can actually make your vendor more of a partner, as long as you both set some ground-rules at the start. Sit down with your vendor, and have a heart-to-heart talk with them, explain that they won’t win every time, but that you’re willing to work with them in an honest way on both sides. Here’s the advice I sent him verbatim. I hope this post generates lots of comments from both customers and vendors. I don’t expect that you’ve had a great experience with your Microsoft reps, but I happen to work with some of the best sales teams in the business, and our clients tell us that all the time. “The key to this relationship is to keep the audience really small. Ideally there should be one person from your side that is responsible for the relationship, and one from the vendor’s side. Each responsible person should have the authority to make decisions, and to bring in other folks as needed for a given topic, project or decision.   For Microsoft, this is called an “Account Manager” – they aren’t technical, they aren’t sales. They “own” a relationship with a company. They learn what the company does, who does it, and how. They are responsible to understand what the challenges in your company are. While they don’t know the bits and bytes of everything we sell, they know what each thing does, and who to talk to about it. I get a call from an Account Manager every week that has pre-digested an issue at an organization and says to me: “I need you to set up an architectural meeting with their technical staff to get a better read on how we can help with problem X.” I do that and then report back to the Account Manager what we learned.  All through this process there’s the atmosphere of a “team”, not a “sales opportunity” per se. I’ve even recommended that the firm use a rival product, and I’ve never gotten push-back on that decision from my Account Managers.   But that brings up an interesting point. Someone pays an Account Manager and pays me. They expect something in return. At some point, you have to buy something. Not every time, not every situation – sometimes it’s just helping you with what you already bought from us. But the point is that you can’t expect lots of love and never spend any money. That’s the way business works.   Finally, don’t view the vendor as someone with their hand in your pocket – somebody that’s just trying to sell you something and doesn’t care if they ever see you again – unless they deserve it. There are plenty of “love them and leave them” companies out there, and you may have even had this experience with us, but that isn’t the case in the firms I work with. In fact, my customers get a questionnaire that asks them that exact question. “How many times have you seen your account team? Did you like your interaction with them? Can they do better?” My raises, performance reviews and general standing in my group are based on the answers the company gives.  Ask your vendor if they measure their sales and support teams this way – if not, seek another vendor to partner with.   Partnering with someone is a big deal. It involves time and effort on your part, and on the vendor’s part. If either of you isn’t pulling your weight, it just won’t work. You have every right to expect them to treat you as a partner, and they have the same right for your side.” Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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• T-SQL Tuesday #34: Help! I Need Somebody!

  - by Most Valuable Yak (Rob Volk)

  Welcome everyone to T-SQL Tuesday Episode 34!  When last we tuned in, Mike Fal (b|t) hosted Trick Shots.  These highlighted techniques or tricks that you figured out on your own which helped you understand SQL Server better. This month, I'm asking you to look back this past week, year, century, or hour...to a time when you COULDN'T figure it out.  When you were stuck on a SQL Server problem and you had to seek help. In the beginning... SQL Server has changed a lot since I started with it.  <Cranky Old Guy> Back in my day, Books Online was neither.  There were no blogs. Google was the third-place search site. There were perhaps two or three community forums where you could ask questions.  (Besides the Microsoft newsgroups...which you had to access with Usenet.  And endure the wrath of...Celko.)  Your "training" was reading a book, made from real dead trees, that you bought from your choice of brick-and-mortar bookstore. And except for your local user groups, there were no conferences, seminars, SQL Saturdays, or any online video hookups where you could interact with a person. You'd have to call Microsoft Support...on the phone...a LANDLINE phone.  And none of this "SQL Family" business!</Cranky Old Guy> Even now, with all these excellent resources available, it's still daunting for a beginner to seek help for SQL Server.  The product is roughly 1247.4523 times larger than it was 15 years ago, and it's simply impossible to know everything about it.*  So whether you are a beginner, or a seasoned pro of over a decade's experience, what do you do when you need help on SQL Server? That's so meta... In the spirit of offering help, here are some suggestions for your topic: Tell us about a person or SQL Server community who have been helpful to you.  It can be about a technical problem, or not, e.g. someone who volunteered for your local SQL Saturday.  Sing their praises!  Let the world know who they are! Do you have any tricks for using Books Online?  Do you use the locally installed product, or are you completely online with BOL/MSDN/Technet, and why? If you've been using SQL Server for over 10 years, how has your help-seeking changed? Are you using Twitter, StackOverflow, MSDN Forums, or another resource that didn't exist when you started? What made you switch? Do you spend more time helping others than seeking help? What motivates you to help, and how do you contribute? Structure your post along the lyrics to The Beatles song Help! Audio or video renditions are particularly welcome! Lyrics must include reference to SQL Server terminology or community, and performances must be in your voice or include you playing an instrument. These are just suggestions, you are free to write whatever you like.  Bonus points if you can incorporate ALL of these into a single post.  (Or you can do multiple posts, we're flexible like that.)  Help us help others by showing how others helped you! Legalese, Your Rights, Yada yada... If you would like to participate in T-SQL Tuesday please be sure to follow the rules below: Your blog post must be published between Tuesday, September 11, 2012 00:00:00 GMT and Wednesday, September 12, 2012 00:00:00 GMT. Include the T-SQL Tuesday logo (above) and hyperlink it back to this post. If you don’t see your post in trackbacks, add the link to the comments below. If you are on Twitter please tweet your blog using the #TSQL2sDay hashtag.  I can be contacted there as @sql_r, in case you have questions or problems with comments/trackback.  I'll have a follow-up post listing all the contributions as soon as I can. Thank you all for participating, and special thanks to Adam Machanic (b|t) for all his help and for continuing this series!

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• YouTube Scalability Lessons

  - by Bertrand Matthelié

  @font-face { font-family: "Arial"; }@font-face { font-family: "Courier New"; }@font-face { font-family: "Wingdings"; }@font-face { font-family: "Calibri"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }h2 { margin: 12pt 0cm 3pt; page-break-after: avoid; font-size: 14pt; font-family: "Times New Roman"; font-style: italic; }a:link, span.MsoHyperlink { color: blue; text-decoration: underline; }a:visited, span.MsoHyperlinkFollowed { color: purple; text-decoration: underline; }span.Heading2Char { font-family: Calibri; font-weight: bold; font-style: italic; }div.Section1 { page: Section1; }ol { margin-bottom: 0cm; }ul { margin-bottom: 0cm; } Very interesting blog post by Todd Hoff at highscalability.com presenting “7 Years of YouTube Scalability Lessons in 30 min” based on a presentation from Mike Solomon, one of the original engineers at YouTube: …. The key takeaway away of the talk for me was doing a lot with really simple tools. While many teams are moving on to more complex ecosystems, YouTube really does keep it simple. They program primarily in Python, use MySQL as their database, they’ve stuck with Apache, and even new features for such a massive site start as a very simple Python program. That doesn’t mean YouTube doesn’t do cool stuff, they do, but what makes everything work together is more a philosophy or a way of doing things than technological hocus pocus. What made YouTube into one of the world’s largest websites? Read on and see... Stats @font-face { font-family: "Arial"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; } 4 billion Views a day 60 hours of video is uploaded every minute 350+ million devices are YouTube enabled Revenue double in 2010 The number of videos has gone up 9 orders of magnitude and the number of developers has only gone up two orders of magnitude. 1 million lines of Python code Stack @font-face { font-family: "Arial"; }@font-face { font-family: "Cambria"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0cm 0cm 0.0001pt; font-size: 12pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; } Python - most of the lines of code for YouTube are still in Python. Everytime you watch a YouTube video you are executing a bunch of Python code. Apache - when you think you need to get rid of it, you don’t. Apache is a real rockstar technology at YouTube because they keep it simple. Every request goes through Apache. Linux - the benefit of Linux is there’s always a way to get in and see how your system is behaving. No matter how bad your app is behaving, you can take a look at it with Linux tools like strace and tcpdump. MySQL - is used a lot. When you watch a video you are getting data from MySQL. Sometime it’s used a relational database or a blob store. It’s about tuning and making choices about how you organize your data. Vitess- a  new project released by YouTube, written in Go, it’s a frontend to MySQL. It does a lot of optimization on the fly, it rewrites queries and acts as a proxy. Currently it serves every YouTube database request. It’s RPC based. Zookeeper - a distributed lock server. It’s used for configuration. Really interesting piece of technology. Hard to use correctly so read the manual Wiseguy - a CGI servlet container. Spitfire - a templating system. It has an abstract syntax tree that let’s them do transformations to make things go faster. Serialization formats - no matter which one you use, they are all expensive. Measure. Don’t use pickle. Not a good choice. Found protocol buffers slow. They wrote their own BSON implementation, which is 10-15 time faster than the one you can download. ...Contiues. Read the blog Watch the video

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• Data management in unexpected places

  - by Ashok_Ora

  Normal 0 false false false EN-US X-NONE X-NONE Data management in unexpected places When you think of network switches, routers, firewall appliances, etc., it may not be obvious that at the heart of these kinds of solutions is an engine that can manage huge amounts of data at very high throughput with low latencies and high availability. Consider a network router that is processing tens (or hundreds) of thousands of network packets per second. So what really happens inside a router? Packets are streaming in at the rate of tens of thousands per second. Each packet has multiple attributes, for example, a destination, associated SLAs etc. For each packet, the router has to determine the address of the next “hop” to the destination; it has to determine how to prioritize this packet. If it’s a high priority packet, then it has to be sent on its way before lower priority packets. As a consequence of prioritizing high priority packets, lower priority data packets may need to be temporarily stored (held back), but addressed fairly. If there are security or privacy requirements associated with the data packet, those have to be enforced. You probably need to keep track of statistics related to the packets processed (someone’s sure to ask). You have to do all this (and more) while preserving high availability i.e. if one of the processors in the router goes down, you have to have a way to continue processing without interruption (the customer won’t be happy with a “choppy” VoIP conversation, right?). And all this has to be achieved without ANY intervention from a human operator – the router is most likely to be in a remote location – it must JUST CONTINUE TO WORK CORRECTLY, even when bad things happen. How is this implemented? As soon as a packet arrives, it is interpreted by the receiving software. The software decodes the packet headers in order to determine the destination, kind of packet (e.g. voice vs. data), SLAs associated with the “owner” of the packet etc. It looks up the internal database of “rules” of how to process this packet and handles the packet accordingly. The software might choose to hold on to the packet safely for some period of time, if it’s a low priority packet. Ah – this sounds very much like a database problem. For each packet, you have to minimally · Look up the most efficient next “hop” towards the destination. The “most efficient” next hop can change, depending on latency, availability etc. · Look up the SLA and determine the priority of this packet (e.g. voice calls get priority over data ftp) · Look up security information associated with this data packet. It may be necessary to retrieve the context for this network packet since a network packet is a small “slice” of a session. The context for the “header” packet needs to be stored in the router, in order to make this work. · If the priority of the packet is low, then “store” the packet temporarily in the router until it is time to forward the packet to the next hop. · Update various statistics about the packet. In most cases, you have to do all this in the context of a single transaction. For example, you want to look up the forwarding address and perform the “send” in a single transaction so that the forwarding address doesn’t change while you’re sending the packet. So, how do you do all this? Berkeley DB is a proven, reliable, high performance, highly available embeddable database, designed for exactly these kinds of usage scenarios. Berkeley DB is a robust, reliable, proven solution that is currently being used in these scenarios. First and foremost, Berkeley DB (or BDB for short) is very very fast. It can process tens or hundreds of thousands of transactions per second. It can be used as a pure in-memory database, or as a disk-persistent database. BDB provides high availability – if one board in the router fails, the system can automatically failover to another board – no manual intervention required. BDB is self-administering – there’s no need for manual intervention in order to maintain a BDB application. No need to send a technician to a remote site in the middle of nowhere on a freezing winter day to perform maintenance operations. BDB is used in over 200 million deployments worldwide for the past two decades for mission-critical applications such as the one described here. You have a choice of spending valuable resources to implement similar functionality, or, you could simply embed BDB in your application and off you go! I know what I’d do – choose BDB, so I can focus on my business problem. What will you do? /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;}

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• Mixing Forms and Token Authentication in a single ASP.NET Application (the Details)

  - by Your DisplayName here!

  The scenario described in my last post works because of the design around HTTP modules in ASP.NET. Authentication related modules (like Forms authentication and WIF WS-Fed/Sessions) typically subscribe to three events in the pipeline – AuthenticateRequest/PostAuthenticateRequest for pre-processing and EndRequest for post-processing (like making redirects to a login page). In the pre-processing stage it is the modules’ job to determine the identity of the client based on incoming HTTP details (like a header, cookie, form post) and set HttpContext.User and Thread.CurrentPrincipal. The actual page (in the ExecuteHandler event) “sees” the identity that the last module has set. So in our case there are three modules in effect: FormsAuthenticationModule (AuthenticateRequest, EndRequest) WSFederationAuthenticationModule (AuthenticateRequest, PostAuthenticateRequest, EndRequest) SessionAuthenticationModule (AuthenticateRequest, PostAuthenticateRequest) So let’s have a look at the different scenario we have when mixing Forms auth and WS-Federation. Anoymous request to unprotected resource This is the easiest case. Since there is no WIF session cookie or a FormsAuth cookie, these modules do nothing. The WSFed module creates an anonymous ClaimsPrincipal and calls the registered ClaimsAuthenticationManager (if any) to transform it. The result (by default an anonymous ClaimsPrincipal) gets set. Anonymous request to FormsAuth protected resource This is the scenario where an anonymous user tries to access a FormsAuth protected resource for the first time. The principal is anonymous and before the page gets rendered, the Authorize attribute kicks in. The attribute determines that the user needs authentication and therefor sets a 401 status code and ends the request. Now execution jumps to the EndRequest event, where the FormsAuth module takes over. The module then converts the 401 to a redirect (302) to the forms login page. If authentication is successful, the login page sets the FormsAuth cookie.   FormsAuth authenticated request to a FormsAuth protected resource Now a FormsAuth cookie is present, which gets validated by the FormsAuth module. This cookie gets turned into a GenericPrincipal/FormsIdentity combination. The WS-Fed module turns the principal into a ClaimsPrincipal and calls the registered ClaimsAuthenticationManager. The outcome of that gets set on the context. Anonymous request to STS protected resource This time the anonymous user tries to access an STS protected resource (a controller decorated with the RequireTokenAuthentication attribute). The attribute determines that the user needs STS authentication by checking the authentication type on the current principal. If this is not Federation, the redirect to the STS will be made. After successful authentication at the STS, the STS posts the token back to the application (using WS-Federation syntax). Postback from STS authentication After the postback, the WS-Fed module finds the token response and validates the contained token. If successful, the token gets transformed by the ClaimsAuthenticationManager, and the outcome is a) stored in a session cookie, and b) set on the context. STS authenticated request to an STS protected resource This time the WIF Session authentication module kicks in because it can find the previously issued session cookie. The module re-hydrates the ClaimsPrincipal from the cookie and sets it.     FormsAuth and STS authenticated request to a protected resource This is kind of an odd case – e.g. the user first authenticated using Forms and after that using the STS. This time the FormsAuth module does its work, and then afterwards the session module stomps over the context with the session principal. In other words, the STS identity wins.   What about roles? A common way to set roles in ASP.NET is to use the role manager feature. There is a corresponding HTTP module for that (RoleManagerModule) that handles PostAuthenticateRequest. Does this collide with the above combinations? No it doesn’t! When the WS-Fed module turns existing principals into a ClaimsPrincipal (like it did with the FormsIdentity), it also checks for RolePrincipal (which is the principal type created by role manager), and turns the roles in role claims. Nice! But as you can see in the last scenario above, this might result in unnecessary work, so I would rather recommend consolidating all role work (and other claims transformations) into the ClaimsAuthenticationManager. In there you can check for the authentication type of the incoming principal and act accordingly. HTH

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• What Counts for a DBA: Humility

  - by drsql

  In football (the American sort, naturally,) there are a select group of players who really hope to never have their names called during the game. They are members of the offensive line, and their job is to protect other players so they can deliver the ball to the goal to score points. When you do hear their name called, it is usually because they made a mistake and the player that they were supposed to protect ended up flat on his back admiring the clouds in the sky instead of advancing towards the goal to scoring point. Even on the rare occasion their name is called for a good reason, it is usually because they were making up for a teammate who had made a mistake and they covered up for them. The role of offensive lineman is a very good analogy for the role of the admin DBA. As a DBA, you are called on to be barely visible and rarely heard, protecting the company data assets tenaciously, even though the enemies to our craft surround us on all sides:. Developers: Cries of ‘foul!’ often ensue when the DBA says that they want data integrity to be stringently enforced and that documentation is needed so they can support systems, mostly because every error occurrence in the enterprise will be initially blamed on the database and fall to the DBA to troubleshoot. Insisting too loudly may bring those cries of ‘foul’ that somewhat remind you of when your 2 year old daughter didn't want to go to bed. The result of this petulance is that the next "enemy" gets involved. Managers: The concerns that motivate DBAs to argue will not excite the kind of manager who gets his technical knowledge from a glossy magazine filled with buzzwords, charts, and pretty pictures. However, the other programmers in the organization will tickle the buzzword void with a stream of new-sounding ideas and technologies constantly, along with warnings that if we did care about data integrity and document things, the budget would explode! In contrast, the arguments for integrity of data and supportability tend to be about as exciting as watching grass grow, and far too many manager types seem to prefer to smoke it than watch it. Packaged Applications: The DBA is rarely given a chance to review a new application that is being demonstrated for the enterprise, and rarer still is the DBA that gets a veto of an application because the database it uses has clearly been created by an architect that won't read a data modeling book because he is already married. More often than not this leads to hours of work for the DBA trying to performance-tune a database with a menagerie of rules that must be followed to stay within the  application support agreement, such as no changing indexes on a third party schema even though there are 10 billion rows instead of the 10 thousand when the system was last optimized. Hardware Failures: Physical disks, networking devices, memory, and backup devices all come with a measure known as ‘mean time before failure’ and it is never listed in centuries or eons. More like years, and the term ‘mean’ indicates that half of the devices are expected to fail before that, which by my calendar means any hour of any day that it wants to fail it will. But the DBA sucks it up and does the task at hand with a humility that makes them nearly invisible to all but the most observant person in the organization. The best DBAs I know are so proactive in their relentless pursuit of perfection that they detect many of the bugs (which they seldom caused) in the system well before they become a problem. In the end the DBA gets noticed for one of same two reasons as the offensive lineman. You make a mistake, like dropping a critical production database that had never been backed up; or when a system crashes for any reason whatsoever and they are on the spot with troubleshooting and system restoration plans that have been well thought out, tested, and tested again. Not because there is any glory in it, but because it is what they do.   Note: The characteristics of the professions referred to in this blog are meant to be overstated stereotypes for humorous effect, and even some DBAs aren't quite this perfect. If you are reading this far and haven’t hand written a 10 page flaming comment about how you are a _______ and you aren’t like this, that is awesome. Not every situation applies to everyone, but if you have never worked with a bad packaged app, a magazine trained manager, programmers that aren’t team players, or hardware that occasionally failed, relax and go have a unicorn sandwich before you wake up.

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