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• How do I create queries to SQL Server tables via Visual Studio when no knowledge about SQL nor Linq?

  - by Kent S. Clarkson

  Let´s be frank, my knowledge regarding SQL language is very low. Nevertheless, my boss gave me the task to build a database application using the following tools: SQL Server and Visual Studio 2008; C#. I use the VS DataSet as a local mirror of the SQL Server. And let´s be frank again, my understanding of the VS Query builder is also very small, I´m finding it quite confusing, actually. So no help to find from Query builder. And my knowledge of Linq is even lower... Perhaps I should mention that the deadline for the project is "aggressively" set, so I have no chance to learn enough about these things during the project. And I´m a bit stupid too, which is no help when it comes to challenges like this (on other occations it might be quite useful though) With these permissions, what should I do (except for killing myself or retire) to be able to query my tables in a sufficient way?

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• JPanel: both implementing my own paintComponent() and rendering children doesn't work

  - by Paul Marshall

  I'm extending a JPanel to display a game board, and adding a JEditorPane at the bottom to hold some status text. Unfortunately, the game board renders just fine, but the JEditorPane is just a blank gray area until I highlight the text in it, when it will render whatever text is highlighted (but not the rest). If I'm understanding Swing right, it should work, because super.paintComponent(g) should render the other children (i.e., the JEditorPane). Tell me, o great stackoverflow, what bonehead mistake am I making? public GameMap extends JPanel { public GameMap() { JEditorPane statusLines = new JEditorPane("text/plain","Stuff"); this.setLayout(new BoxLayout(this,BoxLayout.PAGE_AXIS)); this.add(new Box.Filler(/*enough room to draw my game board*/)); this.add(statusLines); } public void paintComponent(Graphics g){ super.paintComponent(g); for ( all rows ){ for (all columns){ //paint one tile } } } }

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• How to reduce java concurrent mode failure and excessive gc

  - by jimx

  In Java, the concurrent mode failure means that the concurrent collector failed to free up enough memory space form tenured and permanent gen and has to give up and let the full stop-the-world gc kicks in. The end result could be very expensive. I understand this concept but never had a good comprehensive understanding of A) what could cause a concurrent mode failure and B) what's the solution?. This sort of unclearness leads me to write/debug code without much of hints in mind and often has to shop around those performance flags from Foo to Bar without particular reasons, just have to try. I'd like to learn from developers here how your experience is. If you had previous encountered such performance issue, what was the cause and how you addressed it? If you have coding recommendations, please don't be too general. Thanks!

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• What is the JavaScript variable scope in a switch / case statment?

  - by Todd Moses

  While creating JavaScript with ASP.NET MVC I noticed several scope warnings and realized that I am missing something with understanding the variable scope inside the switch / case statement. Warning: 'i' is already defined referring to case b and case c My code looks similar to this: switch(element) { case 'a': for(var i=0; i < count; i++){ do something } break; case 'b': for(var i=0; i < count; i++){ do something } break; case 'c': for(var i=0; i < count; i++){ do something } break; } I thought scope ended with each break statement but it seems that scope does not end until the end of the switch/case. Is scope for the entire switch/case?

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• How does Rails find models and controllers? How can I get it to load more models?

  - by David

  I'm trying to create a non-ActiveRecord model in app/models/gamestate.rb. Then inside my controller (PlayController) I should be able to do GameState.new, right? No go: NameError (uninitialized constant PlayController::GameState): app/controllers/play_controller.rb:23:in `play' (at least in the development environment) But! If I do have a model called app/models/play.rb, then it's automatically loaded and I can do Play.new. So my question is: how does Rails know which classes to load? What sort of name mangling does it do to get from play#action to PlayController to app/controllers/play_controller.rb to app/models/play.rb? It seems awfully fragile, but maybe a better understanding of how this works would help. And finally, how can I get it to load app/models/gamestate.rb?

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• MySQL - Sort on a calculated value based on two dates

  - by Petter Magnusson

  I have the following problem that needs to be solved in a MySQL query: Fields info - textfield date1 - a date field date2 - a date field offset1 - a text field with a number in the first two positions, example "10-High" offset2 - a text field with a number in the first two positions, example "10-High" I need to sort the records by the calculated "sortvalue" based on the current date (today): If today=date2 then sortvalue=offset1*10+offset2*5+1000 else sortvalue=offset1*10+offset2*5 I have quite good understanding of basic SQL with joins etc, but this I am not even sure if its possible...if it helps I could perhaps live with a single formula giving the same sort of effect as the IFs do....ie. before date1 = low value, after date2 = high value... Rgds PM

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• Is there an easy way to convert C# classes to PHP?

  - by John

  I am used to writing C# Windows application. However I have some free hosted PHP web space that I would like to make use of. I have a basic understanding of PHP but have never used it's object oriented capabilities. Is there an easy way to convert C# classes to PHP classes or is it just not possible to write a fully object oriented application in PHP? Update: There are no reliance on the .NET framework beyond the basics. The main aim would be to restructure the class properties, variable enums, etc. The PHP will be hosted on a Linux server.

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• How Java Runtime Maps to Targets

  - by zharvey

  According to the Javadocs for Runtime here: Every Java application has a single instance of class Runtime that allows the application to interface with the environment in which the application is running. The current runtime can be obtained from the getRuntime method. An application cannot create its own instance of this class. My question is: what's their definition of an application? Is each JAR/WAR/EAR considered a standalone application? What about a plain ole' Driver.class class with a main() method? What about JEE containers that house EARs and EJBs? I guess I'm trying to understand how many Runtime instances could be up and running inside a complex (JEE) system. And understanding that requires me to understand what specific "things" constitute an "application" in Java terminology. Thanks in advance!

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• Authentication from url in Restlet

  - by DutrowLLC

  I've been using Restlets "ChallengeResponse" mechanism to authenticate users so far. ChallengeResponse challengeResponse = getRequest().getChallengeResponse(); if( challengeResponse == null ){ throw new RuntimeException("not authenticated"); } String login = challengeResponse.getIdentifier(); String password = new String(challengeResponse.getSecret()); From my understanding, "ChallengeResponse" requires that the username and password are put into headers. However a client needs to put the credentials into the url like so: https://username:[email protected]/my_secure_document When I looked at what was actually sent, it looks like the password is being hashed. What is the proper way to authenticate in this fashion using Restlet?

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• Good learning resources for JNDI implementation (JBoss 5)

  - by iandisme

  I have been working with JavaEE/EJB3 web apps for about half a year now. Until recently, I haven't had to touch a lot of the behind-the-scenes stuff, just the meat of the code. I have been wrestling with JNDI problems, and though I've solved a couple of them, I'm pretty much just doing the whole cargo cult copy-paste routine. It would really help me to better understand JNDI; my understanding of it right now can be summarized as "it's that thing these classes sometimes do to find other classes." My question is, has anyone had success learning JNDI/EJB3/related topics from a book or online content? I've googled for it but the stuff that comes up is old or specific to a certain framework I'm not using. I'm looking for something that's either JBoss-specific or generic enough to be useful anyway.

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• Entity Framework VS LINQ to SQL VS ADO.NET with stored procedures?

  - by BritishDeveloper

  How would you rate each of them in terms of: Performance Speed of development Neat, intuitive, maintainable code Flexibility Overall I like my SQL and so have always been a die-hard fan of ADO.NET and stored procedures but I recently had a play with Linq to SQL and was blown away by how quickly I was writing out my DataAccess layer and have decided to spend some time really understanding either Linq to SQL or EF... or neither? I just want to check, that there isn't a great flaw in any of these technologies that would render my research time useless. E.g. performance is terrible, it's cool for simple apps but can only take you so far

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• Java: Best practices for turning foreign horror-code into clean API...?

  - by java.is.for.desktop

  Hello, everyone! I have a project (related to graph algorithms). It is written by someone else. The code is horrible: public fields, no getters/setters huge methods, all public some classes have over 20 fields some classes have over 5 constructors (which are also huge) some of those constructors just left many fields null (so I can't make some fields final, because then every second constructor signals errors) methods and classes rely on each other in both directions I have to rewrite this into a clean and understandable API. Problem is: I myself don't understand anything in this code. Please give me hints on analyzing and understanding such code. I was thinking, perhaps, there are tools which perform static code analysis and give me call graphs and things like this.

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• What exactly is a Monad?

  - by WeNeedAnswers

  Can someone please explain to me what a Monad is. I think I grasp Monoids and I grasp that they basically control the input of state into a system. I just look at the text in Haskell and glaze over. A simple example in python would be great. My current understanding is that a Monoid is a procedural piece of code that needs to be read from top to bottom in sequence with the output being the input for the function. I think that I may even got that wrong, but hey I am here to learn.

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• Modular enterprise architecture using MVC and Orchard CMS

  - by MrJD

  I'm making a large scale MVC application using Orchard. And I'm going to be separating my logic into modules. I'm also trying to heavily decouple the application for maximum extensibility and testability. I have a rudimentary understanding of IoC, Repository Pattern, Unit of Work pattern and Service Layer pattern. I've made myself a diagram. I'm wondering if it is correct and if there is anything I have missed regarding an extensible application. Note that each module is a separate project.

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• strategies for learning complex software packages

  - by Tom

  I am a fairly novice Java programmer and I am currently working on a project to extend a piece of software that has been developed over a few years. So it has pretty big code base and the previous developers knew it well, so extending it is not going to be easy without a thorough understanding of the structure and function. 1) I had begun by trying to tackle small parts of the system and document them with mindmap. (particularly I am trying to document the interactions with external systems) 2) I have the book "code complete", which I am working through. 3) I have pointed some tools like "tattletale" at the code to get some diagrams of dependency relationships. What other strategies should I employ, should I focus on one particular aspect?

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• Do comments slow down an interpreted language?

  - by mvid

  I am asking this because I use Python, but it could apply to other interpreted languages as well (ruby, php). Whenever I leave a comment in my code, is it slowing down the interpreter? My limited understanding of an interpreter is that it reads program expressions in as strings and converts those strings into code. It seems that every time it parses a comment, that is wasted time. Is this the case? Is there some convention for comments in interpreted languages, or is the effect negligible?

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• What's the ROI of using a build tool like ant or nant?

  - by leeand00

  To me this sounds like a really stupid question. Why would you not use a build tool? However, I need to explain my co-worker why he should be using a build tool of some sort. He's getting really into the idea of working as a team with more programmers, but he isn't understanding the bigger picture of what needs to change in the build process in order to work with a larger team; (i.e. defensive programming/unit testing your code, having a bug database, programming modular libraries, and using sub-repositories to store modules in version control. This is a rather large stack of technologies that I need to prove the ROI of...so I figured I'd start with the ROI of using a build tool rather than just...say...clicking compile.

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• is there a downside to putting N in front of strings in scripts? Is it considered a "best practice"?

  - by jcollum

  Let's say I have a table that has a varchar field. If I do an insert like this: INSERT MyTable SELECT N'the string goes here' Is there any fundamental difference between that and: INSERT MyTable SELECT 'the string goes here' My understanding was that you'd only have a problem if the string contained a Unicode character and the target column wasn't unicode. Other than that, SQL deals with it just fine and converts the string with the N'' into a varchar field (basically ignores the N). I was under the impression that N in front of strings was a good practice, but I'm unable to find any discussion of it that I'd consider definitive. Title may need improvement, feel free.

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• ORM framework that extends base class with database-implementation.

  - by aioobe

  I have a game consisting of a client / server + a webpage. A central notion in both client and game-/webserver is an Account. Accounts are stored in a database thus I'm in need of some ORM and recently had a look at Hibernate and Cayenne. My understanding however, is that both frameworks provide an "DatabaseBackedAccount"-class which I extend with my other Account methods. My problem is that the Account class is reused heavily on the client side, and I would obviously not want to include database-related code on the client implementation. My current solution is to have an Account class (shared by server and client) and extend this with a DatabaseBackedAccount (overriding setter-methods and providing a commit method) on the server side. I find this quite natural and nice, however I've had to implement all gory sql-details and ORM myself. Is there any way to "turn the table" in any existing ORM framework, so that the generated classes extend my existing class?

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• Assigning a MVC Controller property from Asp.Net page

  - by JasonMHirst

  I don't know if I've understanding MVC correctly if my question makes no sense, but I'm trying to understand the following: I have some code on a controller that returns JSON data. The JSON data is populated based on a choice from a dropdown box on an Asp.Net page. I thought (incorrectly) that Session variables would be shared between the Asp.Net project and the MVC Project. What I'd like to do therefore (if this is possible), is to call a Sub on the MVC that sets a variable before the JSON query is run. I have the following: Sub SetCountryID(ByVal CountryID As Integer) Me.pCountrySelectedID = CountryID End Sub Which I can call by the following: Response.Write("http://localhost:7970/Home/SetCountryID/?CountryID=44") But this then results in a blank page - again obviouslly totally incorrect! Am I going about MVC the wrong way or do I still have a hell of a lot more learning to do? Is this even possible to do?

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• How do negated patterns work in .gitignore?

  - by chrisperkins

  I am attempting to use a .gitignore file with negated patterns (lines starting with !), but it's not working the way I expect. As a minimal example, I have the folllowing directory structure: C:/gittest -- .gitignore -- aaa/ -- bbb/ -- file.txt -- ccc/ -- otherfile.txt and in my gitignore file, I have this: aaa/ !aaa/ccc/ My understanding (based on this: http://ftp.sunet.se/pub//Linux/kernel.org/software/scm/git/docs/gitignore.html) is that the file aaa/ccc/otherfile.txt should not be ignored, but in fact git is ignoring everything under aaa. Am I misunderstanding this sentence: "An optional prefix ! which negates the pattern; any matching file excluded by a previous pattern will become included again."? BTW, this is on Windows with msysgit 1.7.0.2.

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• Arrays in database tables and normalization

  - by Ivan Petrov

  Hi! Is it smart to keep arrays in table columns? More precisely I am thinking of the following schema which to my understanding violates normalization: create table Permissions( GroupID int not null default(-1), CategoryID int not null default(-1), Permissions varchar(max) not null default(''), constraint PK_GroupCategory primary key clustered(GroupID,CategoryID) ); and this: create table Permissions( GroupID int not null default(-1), CategoryID int not null default(-1), PermissionID int not null default(-1), constraint PK_GroupCategory primary key clustered(GroupID,CategoryID) ); UPD: Forgot to mention, in the scope of this concrete question we will consider that the "fetch rows that have permission X" won't be performed, instead all the lookups will be made by GroupID and CategoryID only Thoughts? Thanks in advance!

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• How to write a Compiler in C for C

  - by Kerb_z

  I want to write a Compiler for C. This is a Project for my College i am doing as per my University. I am an intermediate programmer in C, with understanding of Data Structures. Now i know a Compiler has the following parts: 1. Lexer 2. Parser 3. Intermediate Code Generator 4. Optimizer 5. Code Generator I want to begin with the Lexer part and move on to Parser. I am consulting the following book: Compilers: Principles, Techniques, and Tools by Alfred V. Aho, Ravi Sethi, Jeffrey D. Ullman. The thing is that this book is highly theoretical and perplexing to me. I really appreciate the authors. But the point is i am not able to begin my project, as if i am blinded where to go. Need guidance please help.

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• Why should I reuse XmlHttpRequest objects?

  - by Xavi

  From what I understand, it's a best practice to reuse XmlHttpRequest objects whenever possible. Unfortunately, I'm having a hard time understanding why. It seems like trying to reuse XHR objects can increase code complexity, introduce possible browser incompatibilities, and lead to other subtle bugs. After researching this question for a while, I did come up with a list of possible explanations: Fewer objects created means less garbage collecting Reusing XHR objects reduces the chance of memory leaks The overhead of creating a new XHR object is high The browser is able to perform some sort of network optimization under hood But I'm not sure if any of these reasons are actually valid. Any light you can shed on this question would be much appreciated.

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• How do I use SDl_Threads properly?

  - by Anoymonous

  I am new to threads,SDL and how graphic work in general. I've been looking through all of LazyFoo's SDL tutorials, and had helped me greatly. But in his tutorials about multi threading, he commented that you should never use video functions in separate threads, or might cause problem. I am curious how it should be done, as I still have a vague understanding of graphics and threads. As one of my projects is a shoot'em up, I was wondering if I should create one thread that displays all the graphics, one threads receives all the player input for his ship, and another thread for the enemy AI. If this is NOT how it should be done, (I think it's wrong) does anyone have any advice of how graphics should be implemented with user input and enemy AI with threads? For the Lazyfoo's tutorials, this is the link: http://lazyfoo.net/SDL_tutorials/

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