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• What is your best-practice advice on implementing SQL stored procedures (in a C# winforms applicatio

  - by JYelton

  I have read these very good questions on SO about SQL stored procedures: When should you use stored procedures? and Are Stored Procedures more efficient, in general, than inline statements on modern RDBMS’s? I am a beginner on integrating .NET/SQL though I have used basic SQL functionality for more than a decade in other environments. It's time to advance with regards to organization and deployment. I am using .NET C# 3.5, Visual Studio 2008 and SQL Server 2008; though this question can be regarded as language- and database- agnostic, meaning that it could easily apply to other environments that use stored procedures and a relational database. Given that I have an application with inline SQL queries, and I am interested in converting to stored procedures for organizational and performance purposes, what are your recommendations for doing so? Here are some additional questions in my mind related to this subject that may help shape the answers: Should I create the stored procedures in SQL using SQL Management Studio and simply re-create the database when it is installed for a client? Am I better off creating all of the stored procedures in my application, inside of a database initialization method? It seems logical to assume that creating stored procedures must follow the creation of tables in a new installation. My database initialization method creates new tables and inserts some default data. My plan is to create stored procedures following that step, but I am beginning to think there might be a better way to set up a database from scratch (such as in the installer of the program). Thoughts on this are appreciated. I have a variety of queries throughout the application. Some queries are incredibly simple (SELECT id FROM table) and others are extremely long and complex, performing several joins and accepting approximately 80 parameters. Should I replace all queries with stored procedures, or only those that might benefit from doing so? Finally, as this topic obviously requires some research and education, can you recommend an article, book, or tutorial that covers the nuances of using stored procedures instead of direct statements?

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• Find unique vertices from a 'triangle-soup'

  - by sum1stolemyname

  I am building a CAD-file converter on top of two libraries (Opencascade and DWF Toolkit). However, my question is plattform agnostic: Given: I have generated a mesh as a list of triangular faces form a model constructed through my application. Each Triangle is defined through three vertexes, which consist of three floats (x, y & z coordinate). Since the triangles form a mesh, most of the vertices are shared by more then one triangle. Goal: I need to find the list of unique vertices, and to generate an array of faces consisting of tuples of three indices in this list. What i want to do is this: //step 1: build a list of unique vertices for each triangle for each vertex in triangle if not vertex in listOfVertices Add vertex to listOfVertices //step 2: build a list of faces for each triangle for each vertex in triangle Get Vertex Index From listOfvertices AddToMap(vertex Index, triangle) While I do have an implementation which does this, step1 (the generation of the list of unique vertices) is really slow in the order of O(n!), since each vertex is compared to all vertices already in the list. I thought "Hey, lets build a hashmap of my vertices' components using std::map, that ought to speed things up!", only to find that generating a unique key from three floating point values is not a trivial task. Here, the experts of stackoverflow come into play: I need some kind of hash-function which works on 3 floats, or any other function generating a unique value from a 3d-vertex position.

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• Newbie question about Java

  - by Rob Nicholson

  Okay, I know that Java is a language but somebody has asked me if they can write a web application to interface in with a web app I've written in ASP.NET. I'm implementing a web service to serve up an XML so it's pretty language agnostic. However, I'm not 100% sure whether going down the Java route makes a lot of sense. I was kind of expecting PHP or ASP.NET server side code with maybe some Ajax/JavaScript or maybe a heavier client JavaScript program using JScript. Could some kind sole explain the basic Java environment when it comes with webapps. I've inferred the following - am I barking up the right tree? Java when run like ASP.NET is called JSP JavaBeans is a bit like the .NET framework, i.e. it's a library of re-usable components Java EE is a bit like ASP.NET in that it's a framework for building web pages on a server Java can also run on the client but it needs the Java VM installing When running Java on the client, can you use JavaBeans and is there a framework? Can it also use JScript? I don't think so as JScript is JavaScript library. Whilst running Java on the server would be okay, this is a relatively small application and therefore Java sounds like a bit of overkill. PHP or ASP.NET feels a better fit. But I don't think they should go down the Java applet in the browser and it adds complexity that's not needed. Thanks, Rob.

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• Workflow engine BPMN, Drools, etc or ESB?

  - by Tom

  We currently have an application that is based on an in-house developed workflow engine with YAML based DSL. We are looking to move parts of it to Java. I have discovered a number of java solutions like Intalio, JBPM, Drools Expert, Drools Flow etc. They appear to be aimed at businesses where the business analyst creates the workflows using a graphical editor and submits them to the workflow engine. They seem geared towards ease of use for non-technical people rather than for developers with a focus on human interaction. The workflows tend to look like. Discover-a-file -\ -> join -> process-file -> move-file -> register-file Discover-some-metadata -/ If any step fails we need to retry it X times. We also need to be able to stop the system and be able to restart it and have it continue from where it was (durable). Some of our workflows can be defined by a set of goals we need to achieve so Jess's backwards rule chaining sounds interesting but it is not open source. It might be that what we are after is a Finite State Machine engine or just an Enterprise Service Bus and do everything as JMS queues. Is there a good open source workflow engine that is both standards-based but also geared towards developers. We don't particular want to use a graphical workflow designer or write reams of XML and it should ideally be in Java or language agnostic (makes REST/Soap calls to external services). Thanks, Tom

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• Is it possible that a single-threaded program is executed simultaneously on more than one CPU core?

  - by Wolfgang Plaschg

  When I run a single-threaded program that i have written on my quad core Intel i can see in the Windows Task Manager that actually all four cores of my CPU are more or less active. One core is more active than the other three, but there is also activity on those. There's no other program (besided the OS kernel of course) running that would be plausible for that activitiy. And when I close my program all activity an all cores drops down to nearly zero. All is left is a little "noise" on the cores, so I'm pretty sure all the visible activity comes directly or indirectly (like invoking system routines) from my program. Is it possible that the OS or the cores themselves try to balance some code or execution on all four cores, even it's not a multithreaded program? Do you have any links that documents this technique? Some infos to the program: It's a console app written in Qt, the Task Manager states that only one thread is running. Maybe Qt uses threads, but I don't use signals or slots, nor any GUI. Link to Task Manager screenshot: http://img97.imageshack.us/img97/6403/taskmanager.png This question is language agnostic and not tied to Qt/C++, i just want to know if Windows or Intel do to balance also single-threaded code on all cores. If they do, how does this technique work? All I can think of is, that kernel routines like reading from disk etc. is scheduled on all cores, but this won't improve performance significantly since the code still has to run synchronous to the kernel api calls. EDIT Do you know any tools to do a better analysis of single and/or multi-threaded programs than the poor Windows Task Manager?

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• Why is OpenSubKey() returning null on my Win 7 64 bit system?

  - by BrMcMullin

  Has anyone seen OpenSubKey() and other Microsoft.Win32 registry functions return null on 64 bit systems when 32 bit registry keys are under Wow6432node in the registry? I'm working on a unit testing framework that makes a call to OpenSubKey() from the .net library. My dev system is a Win 7 64 bit environment with VS 2008 SP1 and the Win 7 SDK installed. The application we're unit testing is a 32 bit application, so the registry is virtualized under HKLM\Software\Wow6432node. When we call: Registry.LocalMachine.OpenSubKey( @"Software\MyCompany\MyApp\" ); Null is returned, however explicitly stating to look here works: Registry.LocalMachine.OpenSubKey( @"Software\Wow6432node\MyCompany\MyApp\" ); From what I understand this function should be agnostic to 32 bit or 64 bit environments and should know to jump to the virtual node. Even stranger is the fact that the exact same call inside a compiled and installed version of our application is running just fine on the same system and is getting the registry keys necessary to run; which are also being placed in HKLM\Software\Wow6432node. Any suggestions? Thanks in advance!

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• mod_cgi , mod_fastcgi, mod_scgi , mod_wsgi, mod_python, FLUP. I don't know how many more. what is mo

  - by claws

  I recently learnt Python. I liked it. I just wanted to use it for web development. This thought caused all the troubles. But I like these troubles :) Coming from PHP world where there is only one way standardized. I expected the same and searched for python & apache. http://stackoverflow.com/questions/449055/setting-up-python-on-windows-apache says Stay away from mod_python. One common misleading idea is that mod_python is like mod_php, but for python. That is not true. So what is equivalent of mod_php in python? I need little clarification on this one http://stackoverflow.com/questions/219110/how-python-web-frameworks-wsgi-and-cgi-fit-together CGI, FastCGI and SCGI are language agnostic. You can write CGI scripts in Perl, Python, C, bash, or even Assembly :). So, I guess mod_cgi , mod_fastcgi, mod_scgi are their corresponding apache modules. Right? WSGI is some kind of optimized/improved inshort an efficient version specifically designed for python language only. In order to use this mod_wsgi is a way to go. right? This leaves out mod_python. What is it then? Apache - mod_fastcgi - FLUP (via CGI protocol) - Django (via WSGI protocol) Flup is another way to run with wsgi for any webserver that can speak FCGI, SCGI or AJP What is FLUP? What is AJP? How did Django come in the picture? These questions raise quetions about PHP. How is it actually running? What technology is it using? mod_php & mod_python what are the differences? In future if I want to use Perl or Java then again will I have to get confused? Kindly can someone explain things clearly and give a Complete Picture.

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• Great examples of self-paced labs and exercises

  - by Mayo

  It is probably a safe bet that many of us are what they call Tactile / Kinesthetic Learners meaning that we learn best when we are physically doing something as opposed to listening to an online tutorial or reading a book. My goal with this question is to derive a list of books or online resources that serve as superb examples of self-paced programming labs and exercises. For example, I was extremely impressed with the SportsStore exercise in Steven Sanderson's Pro ASP.NET MVC Framework. The exercise spanned multiple chapters and gradually introduced new topics. I was also impressed with the materials associated with the Windows Azure Boot Camp. The demos and lab materials, accessible through the website, allow us to practice and reinforce what we can read about in articles and books. Please list any examples you might have, one per submission, below. The question is language/platform agnostic. Suggestions can be generic or specific to a given technology (PHP, SQL Server, Azure, Flash, Objective C, etc.). I only ask that the answers pertain to labs and exercises that relate to programming. My hope is that the best answers will float to the top allowing developers to review the top answers and find another programming topic that can be learned through example.

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• Parsing basic math equations for children's educational software?

  - by Simucal

  Inspired by a recent TED talk, I want to write a small piece of educational software. The researcher created little miniature computers in the shape of blocks called "Siftables". [David Merril, inventor - with Siftables in the background.] There were many applications he used the blocks in but my favorite was when each block was a number or basic operation symbol. You could then re-arrange the blocks of numbers or operation symbols in a line, and it would display an answer on another siftable block. So, I've decided I wanted to implemented a software version of "Math Siftables" on a limited scale as my final project for a CS course I'm taking. What is the generally accepted way for parsing and interpreting a string of math expressions, and if they are valid, perform the operation? Is this a case where I should implement a full parser/lexer? I would imagine interpreting basic math expressions would be a semi-common problem in computer science so I'm looking for the right way to approach this. For example, if my Math Siftable blocks where arranged like: [1] [+] [2] This would be a valid sequence and I would perform the necessary operation to arrive at "3". However, if the child were to drag several operation blocks together such as: [2] [\] [\] [5] It would obviously be invalid. Ultimately, I want to be able to parse and interpret any number of chains of operations with the blocks that the user can drag together. Can anyone explain to me or point me to resources for parsing basic math expressions? I'd prefer as much of a language agnostic answer as possible.

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• How to setup Lucene search for a B2B web app?

  - by Bill Paetzke

  Given: 5000 databases (spread out over 5 servers) 1 database per client (so you can infer there are 1000 clients) 2 to 2000 users per client (let's say avg is 100 users per client) Clients (databases) come and go every day (let's assume most remain for at least one year) Let's stay agnostic of language or sql brand, since Lucene (and Solr) have a breadth of support The Question: How would you setup Lucene search so that each client can only search within its database? How would you setup the index(es)? Would you need to add a filter to all search queries? If a client cancelled, how would you delete their (part of the) index? (this may be trivial--not sure yet) Possible Solutions: Make an index for each client (database) Pro: Search is faster (than one-index-for-all method). Indices are relative to the size of the client's data. Con: I'm not sure what this entails, nor do I know if this is beyond Lucene's scope. Have a single, gigantic index with a database_name field. Always include database_name as a filter. Pro: Not sure. Maybe good for tech support or billing dept to search all databases for info. Con: Search is slower (than index-per-client method). Flawed security if query filter removed. For Example: Joel Spolsky said in Podcast #11 that his hosted web app product, FogBugz On-Demand, uses Lucene. He has thousands of on-demand clients. And each client gets their own database. His situation is quite similar to mine. Although, he didn't elaborate on the setup (particularly indices); hence, the need for this question. One last thing: I would also accept an answer that uses Solr (the extension of Lucene). Perhaps it's better suited for this problem. Not sure.

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• Why put a DAO layer over a persistence layer (like JDO or Hibernate)

  - by Todd Owen

  Data Access Objects (DAOs) are a common design pattern, and recommended by Sun. But the earliest examples of Java DAOs interacted directly with relational databases -- they were, in essence, doing object-relational mapping (ORM). Nowadays, I see DAOs on top of mature ORM frameworks like JDO and Hibernate, and I wonder if that is really a good idea. I am developing a web service using JDO as the persistence layer, and am considering whether or not to introduce DAOs. I foresee a problem when dealing with a particular class which contains a map of other objects: public class Book { // Book description in various languages, indexed by ISO language codes private Map<String,BookDescription> descriptions; } JDO is clever enough to map this to a foreign key constraint between the "BOOKS" and "BOOKDESCRIPTIONS" tables. It transparently loads the BookDescription objects (using lazy loading, I believe), and persists them when the Book object is persisted. If I was to introduce a "data access layer" and write a class like BookDao, and encapsulate all the JDO code within this, then wouldn't this JDO's transparent loading of the child objects be circumventing the data access layer? For consistency, shouldn't all the BookDescription objects be loaded and persisted via some BookDescriptionDao object (or BookDao.loadDescription method)? Yet refactoring in that way would make manipulating the model needlessly complicated. So my question is, what's wrong with calling JDO (or Hibernate, or whatever ORM you fancy) directly in the business layer? Its syntax is already quite concise, and it is datastore-agnostic. What is the advantage, if any, of encapsulating it in Data Access Objects?

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• Comet, responseText and memory usage

  - by ithcy

  Is there a way to clear out the responseText of an XHR object without destroying the XHR object? I need to keep a persistent connection open to a web server to feed live data to a browser. The problem is, there is a relatively large amount of data coming through (several hundred K per second constantly), so memory usage is a big problem, because this connection must remain open for at least several minutes. responseText gets very big very quickly, even though the JSON I send back has been crunched as small as it can get. Due to the way the server-side app works, if I use AJAX-style short polling and just destroy the XHR object when I'm done with it, I miss significant amounts of important data even in the few milliseconds it takes to parse the response, create a new XHR and send it out. I do not have the option to use overlapping requests, as the web server only accepts one connection at a time. (Don't ask.) So Comet is exactly the model I need. What I would like to do is parse each JSON chunk as it comes back from the server, and then clear out responseText so that I can keep using the same connection. However, responseText is read-only. It cannot be directly emptied by any method I have found. Is there a part of the picture I am missing here? Does anyone know any tricks I can use to free up responseText when I'm done reading it? Or is there another place the server responses can go? I am not including code because this is really almost a code-agnostic question. The Javascript routines that spawn the XHRs and handle the returned data are very, very simple.

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• Embedding Lua functions as member variables in Java

  - by Zarion

  Although the program I'm working on is in Java, answering this from a C perspective is also fine, considering that most of this is either language-agnostic, or happens on the Lua side of things. In the outline I have for the architecture of a game I'm programming, individual types of game objects within a particular class (eg: creatures, items, spells, etc.) are loaded from a data file. Most of their properties are simple data types, but I'd like a few of these members to actually contain simple scripts that define, for example, what an item does when it's used. The scripts will be extremely simple, since all fundamental game actions will be exposed through an API from Java. The Lua is simply responsible for stringing a couple of these basic functions together, and setting arguments. The question is largely about the best way to store a reference to a specific Lua function as a member of a Java class. I understand that if I store the Lua code as a string and call lua_dostring, Lua will compile the code fresh every time it's called. So the function needs to be defined somehow, and a reference to this specific function wrapped in a Java function object. One possibility that I've considered is, during the data loading process, when the loader encounters a script definition in a data file, it extracts this string, decorates the function name using the associated object's unique ID, calls lua_dostring on the string containing a full function definition, and then wraps the generated function name in a Java function object. A function declared in script run with lua_dostring should still be added to the global function table, correct? I'm just wondering if there's a better way of going about this. I admit that my knowledge of Lua at this point is rather superficial and theoretical, so it's possible that I'm overlooking something obvious.

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• What ORM for .NET should I use?

  - by eKek0

  I'm relatively new to .NET and have being using Linq2Sql for a almost a year, but it lacks some of the features I'm looking for now. I'm going to start a new project in which I want to use an ORM with the following characteristics: It has to be very productive, I don't want to be dealing with the access layer to save or retrieve objects from or to the database, but it should allows me to easily tweak any object before actually commit it to the database; also it should allows me to work easily with a changing database schema It should allows me to extend the objects mapped from the database, for example to add virtual attributes to them (virtual columns to a table) It has to be (at least almost) database agnostic, it should allows me to work with different databases in a transparent way It has to have not so much configuration or must be based on conventions to make it work It should allows me to work with Linq So, do you know any ORM that I could use? Thank you for your help. EDIT I know that an option is to use NHibernate. This appears as the facto standard for enterprise level applications, but also it seems that is not very productive because its deep learning curve. In other way, I have read in some other post here in SO that it doesn't integrate well with Linq. Is all of that true?

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• High memory usage for dummies

  - by zaf

  I've just restarted my firefox web browser again because it started stuttering and slowing down. This happens every other day due to (my understanding) of excessive memory usage. I've noticed it takes 40M when it starts and then, by the time I notice slow down, it goes to 1G and my machine has nothing more to offer unless I close other applications. I'm trying to understand the technical reasons behind why its such a difficult problem to sol ve. Mozilla have a page about high memory usage: http://support.mozilla.com/en-US/kb/High+memory+usage But I'm looking for a slightly more in depth and satisfying explanation. Not super technical but enough to give the issue more respect and please the crowd here. Some questions I'm already pondering (they could be silly so take it easy): When I close all tabs, why doesn't the memory usage go all the way down? Why is there no limits on extensions/themes/plugins memory usage? Why does the memory usage increase if it's left open for long periods of time? Why are memory leaks so difficult to find and fix? App and language agnostic answers also much appreciated.

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• Web-app currency input/manipulation/calculation with javascript .. there has got to be a better (fra

  - by dreftymac

  BACKGROUND: I am of the "user-input-lockdown" school of thought. Whenever possible, I try to mistrust and sanitize user input, both client side and server side; and I try to take multiple opportunities to restrict possible inputs to a known subset of possibilities, usually this means providing a lot of checkboxes and select lists. (This is from the usability side of things, I know security-wise that malicious users can easily bypass fixed user input GUI controls). PROBLEM: Anyway, the problem always arises with non-fixed input of currency. Whenever I have to accept a freely-specified dollar amount as user input, I always have to confront these problems/annoyances and it is always painful: 1) Make sure to give the user two input boxes for each currency_datapoint, one for the whole_dollar_part and another for the fractional_pennies_part 2) Whenever the user changes a currency_datapoint, provide keystroke-by-keystroke GUI feedback to let them know whether the currency_datapoint is well-formed, with context-appropriate validation rules (e.g., no negatives?, nonzero only?, numeric only!, no non-numeric punctuation! no symbols!) 3) For display purposes, every user-provided currency_datapoint should be translated to human-readable currency formatting (dollar sign, period, commas provided by the app, where appropriate) 4) For calculation purposes, every user-provided currency_datapoint has to be converted to integer (all pennies, to avoid floating point errors) and summed into a grand total with zero or more subtotals. 5) Every user-provided currency_datapoint should be displayed or displayable in a nice "tabular" format, which auto-updates as the user enters each currency_datapoint, including a baloon that warns when one or more currency_datapoints is not well-formed. I seem to be re-inventing this wheel every time I have to work with currency in Javascript on the client side (server side is a bit more flexible since most programming languages have higher-level currency formatting logic). QUESTION: Has anyone out there solved the problem of dealing with the above issues, client side, in a way that is server-side-technology-stack agnostic, (preferrably plain javascript or jquery)? This is getting old, there has to be a better way.

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• confused about how to use JSON in C#

  - by Josh

  The answer to just about every single question about using C# with json seems to be "use JSON.NET" but that's not the answer I'm looking for. the reason I say that is, from everything I've been able to read in the documentation, JSON.NET is basically just a better performing version of the DataContractSerializer built into the .net framework... Which means if I want to deserialize a JSON string, I have to define the full, strongly-typed class for EVERY request I might have. so if I have a need to get categories, posts, authors, tags, etc, I have to define a new class for every one of these things. This is fine if I built the client and know exactly what the fields are, but I'm using someone else's api, so I have no idea what the contract is unless I download a sample response string and create the class manually from the JSON string. Is that the only way it's done? Is there not a way to have it create a kind of hashtable that can be read with json["propertyname"]? Finally, if I do have to build the classes myself, what happens when the API changes and they don't tell me (as twitter seems to be notorious for doing)? I'm guessing my entire project will break until I go in and update the object properties... So what exactly is the general workflow when working with JSON? And by general I mean library-agnostic. I want to know how it's done in general, not specifically to a target library... I hope that made sense, this has been a very confusing area to get into... thanks!

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• What constitutes a development environment, and how do you document it?

  - by Joel Coehoorn

  What items go into a software shop's development environment, how do you document it, and what processes do you follow to make changes? I thinking about this from the standpoint where I want to make it easier to bring new hires up to speed quickly by having all this on a checklist we follow when setting them up, and then while I'm at it making it easier for the new hires or existing team members to bring new powerful toolkits and ideas into the environment without disrupting things. I want to keep this platform agnostic, so even though I'm currently at a microsoft shop where Visual Studio would be assumed I'll go ahead and list compiler/IDE as one of the items: Here are some ideas for part 1: [edit]: I'm keeping this updated based on the better suggestions. Source Control access Issue/Bug/Project tracker System Documention, or references to find the system documentation in source control or in a wiki, including: build document/environment covered by this question design documents / technical notes Coding Style guidelines Deploy for review/testing/QA/staging/production procedures Licensing details for your tools and your product Team Calendar, including the project schedule(s), deadlines, vacation time, and support/on-call schedule (if required) compiler/IDE compiler/IDE extensions (things like source control plugins or visual studio add-ins) 3rd party SDKs/toolkits Database connection and tools Testing Frameworks Internal libraries communication tools (chat, wiki, etc) Static analysis tools (FxCop, FlawFinder, etc) Virtual machines (holding dev environment or for testing) Specialized editors (modeling, xml, etc) Other tools What else goes in this list, and how do you document it and vet changes?

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• C# Virtual method call in constructor - how to refactor?

  - by Cristi Diaconescu

  I have an abstract class for database-agnostic cursor actions. Derived from that, there are classes that implement the abstract methods for handling database-specific stuff. The problem is, the base class ctor needs to call an abstract method - when the ctor is called, it needs to initialize the database-specific cursor. I know why this shouldn't be done, I don't need that explanation! This is my first implementation, that obviously doesn't work - it's the textbook "wrong way" of doing it. The overridden method accesses a field from the derived class, which is not yet instantiated: public abstract class CursorReader { private readonly int m_rowCount; protected CursorReader() { m_rowCount = CreateCursor(sqlCmd); //virtual call ! } protected abstract int CreateCursor(string sqlCmd); } public class SqlCursorReader : CursorReader { private SqlConnection m_sqlConnection; public SqlCursorReader(string sqlCmd, SqlConnection sqlConnection) { m_sqlConnection = sqlConnection; //field initialized here } protected override int CreateCursor(string sqlCmd) { //uses not-yet-initialized member *m_sqlConnection* //so this throws a NullReferenceException var cursor = new CustomCursor(sqlCmd, m_sqlConnection); return cursor.Count(); } } I will follow up with an answer on my attempts to fix this...

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• Argument type deduction, references and rvalues

  - by uj2

  Consider the situation where a function template needs to forward an argument while keeping it's lvalue-ness in case it's a non-const lvalue, but is itself agnostic to what the argument actually is, as in: template <typename T> void target(T&) { cout << "non-const lvalue"; } template <typename T> void target(const T&) { cout << "const lvalue or rvalue"; } template <typename T> void forward(T& x) { target(x); } When x is an rvalue, instead of T being deduced to a constant type, it gives an error: int x = 0; const int y = 0; forward(x); // T = int forward(y); // T = const int forward(0); // Hopefully, T = const int, but actually an error forward<const int>(0); // Works, T = const int It seems that for forward to handle rvalues (without calling for explicit template arguments) there needs to be an forward(const T&) overload, even though it's body would be an exact duplicate. Is there any way to avoid this duplication?

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• What's the best way to communicate the purpose of a string parameter in a public API?

  - by Dave

  According to the guidance published in New Recommendations for Using Strings in Microsoft .NET 2.0, the data in a string may exhibit one of the following types of behavior: A non-linguistic identifier, where bytes match exactly. A non-linguistic identifier, where case is irrelevant, especially a piece of data stored in most Microsoft Windows system services. Culturally-agnostic data, which still is linguistically relevant. Data that requires local linguistic customs. Given that, I'd like to know the best way to communicate which behavior is expected of a string parameter in a public API. I wasn't able to find an answer in the Framework Design Guidelines. Consider the following methods: f(string this_is_a_linguistic_string) g(string this_is_a_symbolic_identifier_so_use_ordinal_compares) Is variable naming and XML documentation the best I can do? Could I use attributes in some way to mark the requirements of the string? Now consider the following case: h(Dictionary<string, object> dictionary) Note that the dictionary instance is created by the caller. How do I communicate that the callee expects the IEqualityComparer<string> object held by the dictionary to perform, for example, a case-insensitive ordinal comparison?

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• How to write these two queries for a simple data warehouse, using ANSI SQL?

  - by morpheous

  I am writing a simple data warehouse that will allow me to query the table to observe periodic (say weekly) changes in data, as well as changes in the change of the data (e.g. week to week change in the weekly sale amount). For the purposes of simplicity, I will present very simplified (almost trivialized) versions of the tables I am using here. The sales data table is a view and has the following structure: CREATE TABLE sales_data ( sales_time date NOT NULL, sales_amt double NOT NULL ) For the purpose of this question. I have left out other fields you would expect to see - like product_id, sales_person_id etc, etc, as they have no direct relevance to this question. AFAICT, the only fields that will be used in the query are the sales_time and the sales_amt fields (unless I am mistaken). I also have a date dimension table with the following structure: CREATE TABLE date_dimension ( id integer NOT NULL, datestamp date NOT NULL, day_part integer NOT NULL, week_part integer NOT NULL, month_part integer NOT NULL, qtr_part integer NOT NULL, year_part integer NOT NULL, ); which partition dates into reporting ranges. I need to write queries that will allow me to do the following: Return the change in week on week sales_amt for a specified period. For example the change between sales today and sales N days ago - where N is a positive integer (N == 7 in this case). Return the change in change of sales_amt for a specified period. For in (1). we calculated the week on week change. Now we want to know how that change is differs from the (week on week) change calculated last week. I am stuck however at this point, as SQL is my weakest skill. I would be grateful if an SQL master can explain how I can write these queries in a DB agnostic way (i.e. using ANSI SQL).

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• IE8 ignores jQuery UI 'dialog' minHeight and height settings

  - by Kev

  I'm using jQuery 1.4.4 with jQueryUI 1.8.7 to display a modal dialog box. I'm having a problem where IE8 renders a scrollbar and appears to ignore the minHeight and height options in all the many different combinations I've tried them in. In Chrome 8 and Firefox 3.6 my dialogue looks like: In IE 8 it looks like: The markup and script looks like: <a id="create" href="#">Create New Thing</a> <div id="dlg-create-thing" title="Create new thing?"> <form name="create-thing-form" id="dlg-create-thing-form"> <p style="text-align:left"> <span>Name: <input id="thingName" name="thingName" maxlength="12" size="30" /></span> <br /><br /> <b>Thing options:</b><br /><br /> <input type="radio" id="option1" name="theoptions" value="0" checked="checked" />Use this option<br /> <input type="radio" id="option1AndMem" name="theoptions" value="1" />Use this other option </p> </form> </div> <script type="text/javascript"> $(function () { $("#dlg-create-thing").dialog({ autoOpen: false, resizable: false, width: 500, modal: true, minHeight: 280, buttons: { "Create": function () { /* do stuff */ }, "Cancel": function () { /* do other stuff */} } }); $("body").delegate("a[id='create']", "click", function () { $("#dlg-create-thing").dialog('open'); return false; } ); }); </script> How can I fix this (preferably in a nice browser agnostic way, but I'd settle for anything)?

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• Multithreading: Read from / write to a pipe

  - by Tero Jokinen

  I write some data to a pipe - possibly lots of data and at random intervals. How to read the data from the pipe? Is this ok: in the main thread (current process) create two more threads (2, 3) the second thread writes sometimes to the pipe (and flush-es the pipe?) the 3rd thread has infinite loop which reads the pipe (and then sleeps for some time) Is this so far correct? Now, there are a few thing I don't understand: do I have to lock (mutex?) the pipe on write? IIRC, when writing to pipe and its buffer gets full, the write end will block until I read the already written data, right? How to check for read data in the pipe, not too often, not too rarely? So that the second thread wont block? Is there something like select for pipes? It is possible to set the pipe to unbuffered more or I have to flush it regularly - which one is better? Should I create one more thread, just for flushing the pipe after write? Because flush blocks as well, when the buffer is full, right? I just don't want the 1st and 2nd thread to block.... [Edit] Sorry, I thought the question is platform agnostic but just in case: I'm looking at this from Win32 perspective, possibly MinGW C...

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• Custom stream wrappers, what could they be useful for in web applications?

  - by michael

  I suppose the concept is language agnostic, but I don't know what it's called in other languages. In PHP they're Stream Wrappers. In short, a wrapper class that allows manipulation of a streamable resource (resource that can be read to/written to/seek into, such as a file, a db, an url). For example, in a template engine (a view), upon including a template file such as: include "view.wrapper://path/to/my/template/file.phtml"; my custom wrapper, declared elsewhere and associated with "view.wrapper", would first intercepts the file to replace such things as short tags (<?=) with a more verbose counterpart (<?php echo). This allows developers to use short tags in views, even if the server isn't set to allow it. It can also be applied to the preprocessing of views pseudo syntax such as {@myVar} (e.g. replacing it with $this->myVar). This is only one application of custom stream wrappers, but the feature seems powerful enough to make me think that there are others that could make life a lot simpler for developers. What have you built, or thought about building, custom stream wrappers for? where have you seen some interesting implementations? I'm particularly interested in their applications in web development.

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