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• CodePlex Daily Summary for Tuesday, September 25, 2012

  CodePlex Daily Summary for Tuesday, September 25, 2012Popular ReleasesRawr: Rawr 5.0.0: This is the Downloadable WPF version of Rawr!For web-based version see http://elitistjerks.com/rawr.php You can find the version notes at: http://rawr.codeplex.com/wikipage?title=VersionNotes Rawr Addon (NOT UPDATED YET FOR MOP)We now have a Rawr Official Addon for in-game exporting and importing of character data hosted on Curse. The Addon does not perform calculations like Rawr, it simply shows your exported Rawr data in wow tooltips and lets you export your character to Rawr (including ba...Coevery - Free CRM: Coevery 1.0.0.26: The zh-CN issue has been solved. We also add a project management module.VidCoder: 1.4.1 Beta: Updated to HandBrake 4971. This should fix some issues with stuck PGS subtitles. Fixed build break which prevented pre-compiled XML serializers from showing up. Fixed problem where a preset would get errantly marked as modified when re-opening the encode settings window or importing a new preset.D3 Loot Tracker: 1.3: Added the ability to reload a previous session to be able to resume it. Removed goblin detection, let's keep this an item tracking utility only. Fixed a bug with crafting sound setting not working properly. Completely re-styled the UI.JSLint for Visual Studio 2010: 1.4.0: VS2012 support is alphaBlackJumboDog: Ver5.7.2: 2012.09.23 Ver5.7.2 (1)InetTest?? (2)HTTP?????????????????100???????????Player Framework by Microsoft: Player Framework for Windows 8 (Preview 6): IMPORTANT: List of breaking changes from preview 5 Added separate samples download with .vsix dependencies instead of source dependencies Support for FreeWheel SmartXML ad responses Support for Smooth Streaming SDK DownloaderPlugins Support for VMAP and TTML polling for live scenarios Support for custom smooth streaming byte stream and scheme handlers Support for new play time and position tracking plugin Added IsLiveChanged event Added AdaptivePlugin.MaxBitrate property Add...WPF Application Framework (WAF): WPF Application Framework (WAF) 2.5.0.8: Version: 2.5.0.8 (Milestone 8): This release contains the source code of the WPF Application Framework (WAF) and the sample applications. Requirements .NET Framework 4.0 (The package contains a solution file for Visual Studio 2010) The unit test projects require Visual Studio 2010 Professional Changelog Legend: [B] Breaking change; [O] Marked member as obsolete WAF: Mark the class DataModel as serializable. InfoMan: Minor improvements. InfoMan: Add unit tests for all modules. Othe...LogicCircuit: LogicCircuit 2.12.9.20: Logic Circuit - is educational software for designing and simulating logic circuits. Intuitive graphical user interface, allows you to create unrestricted circuit hierarchy with multi bit buses, debug circuits behavior with oscilloscope, and navigate running circuits hierarchy. Changes of this versionToolbars on text note dialog are more flexible now. You can select font face, size, color, and background of text you are typing. RAM now can be initialized to one of the following: random va...SiteMap Editor for Microsoft Dynamics CRM 2011: SiteMap Editor (1.1.2020.421): New features: Disable a specific part of SiteMap to keep the data without displaying them in the CRM application. It simply comments XML part of the sitemap (thanks to rboyers for this feature request) Right click an item and click on "Disable" to disable it Items disabled are greyed and a suffix "- disabled" is added Right click an item and click on "Enable" to enable it Refresh list of web resources in the web resources pickerHigLabo: HigLabo_20120919: Add XXXAsync method to all Client class for async await pattern. (HttpClient,BoxNetClient,DropboxClient,FacebookClient,FtpClient,RssClient,SugarSyncClient,TwitterClient,WindowsLiveClient) Add all api to HigLabo.Net.Ftp project. Add strong name to all assembly. Add HttpBodyMultipartFormData to provide upload multipart form data with http protocol. Add HttpBodyFormUrlEncodedData to provide form url encoded post data with http protocol. FacebookClient,RssClient,WindowsLiveClient,BoxNetClient cl...AJAX Control Toolkit: September 2012 Release: AJAX Control Toolkit Release Notes - September 2012 Release Version 60919September 2012 release of the AJAX Control Toolkit. AJAX Control Toolkit .NET 4.5 – AJAX Control Toolkit for .NET 4.5 and sample site (Recommended). AJAX Control Toolkit .NET 4 – AJAX Control Toolkit for .NET 4 and sample site (Recommended). AJAX Control Toolkit .NET 3.5 – AJAX Control Toolkit for .NET 3.5 and sample site (Recommended). Notes: - The current version of the AJAX Control Toolkit is not compatible with ...Sense/Net CMS - Enterprise Content Management: SenseNet 6.1.2 Community Edition: Sense/Net 6.1.2 Community EditionMain new featuresOur current release brings a lot of bugfixes, including the resolution of js/css editing cache issues, xlsx file handling from Office, expense claim demo workspace fixes and much more. Besides fixes 6.1.2 introduces workflow start options and other minor features like a reusable Reject client button for approval scenarios and resource editor enhancements. We have also fixed an issue with our install package to bring you a flawless installation...Solution Extender for Microsoft Dynamics CRM 2011: Solution Extender (2.0.0.6): Fix a problem when serializing entity records (this fix the problem when exporting queues)Visual C++ Directories Editor: VC++ Directories 2012 Editor v1.0 ML (x32-x64): version 1.0 ML for Visual C++ 2012WinRT XAML Toolkit: WinRT XAML Toolkit - 1.2.3: WinRT XAML Toolkit based on the Windows 8 RTM SDK. Download the latest source from the SOURCE CODE page. For compiled version use NuGet. You can add it to your project in Visual Studio by going to View/Other Windows/Package Manager Console and entering: PM> Install-Package winrtxamltoolkit Features AsyncUI extensions Controls and control extensions Converters Debugging helpers Imaging IO helpers VisualTree helpers Samples Recent changes NOTE: Namespace changes DebugConsol...Python Tools for Visual Studio: 1.5 RC: PTVS 1.5RC Available! We’re pleased to announce the release of Python Tools for Visual Studio 1.5 RC. Python Tools for Visual Studio (PTVS) is an open-source plug-in for Visual Studio which supports programming with the Python language. PTVS supports a broad range of features including CPython/IronPython, Edit/Intellisense/Debug/Profile, Cloud, HPC, IPython, etc. support. The primary new feature for the 1.5 release is Django including Azure support! The http://www.djangoproject.com is a pop...Launchbar: Lanchbar 4.0.0: This application requires .NET 4.5 which you can find here: www.microsoft.com/visualstudio/downloadsAssaultCube Reloaded: 2.5.4 -: Linux has Ubuntu 11.10 32-bit precompiled binaries and Ubuntu 10.10 64-bit precompiled binaries, but you can compile your own as it also contains the source. If you are using Mac or other operating systems, please wait while we try to package for those OSes. Try to compile it. If it fails, download a virtual machine. The server pack is ready for both Windows and Linux, but you might need to compile your own for Linux (source included) Changelog: New logo Improved airstrike! Reset nukes...Extended WPF Toolkit: Extended WPF Toolkit - 1.7.0: Want an easier way to install the Extended WPF Toolkit?The Extended WPF Toolkit is available on Nuget. What's new in the 1.7.0 Release?New controls Zoombox Pie New features / bug fixes PropertyGrid.ShowTitle property added to allow showing/hiding the PropertyGrid title. Modifications to the PropertyGrid.EditorDefinitions collection will now automatically be applied to the PropertyGrid. Modifications to the PropertyGrid.PropertyDefinitions collection will now be reflected automaticaly...New ProjectsAffine transformations (Iterated function system): Small app for generating fractals using iterated function system.aspnet mvc store: Lite ASP.NET MVC CMSAugmented Reality: .Autocomplete: AutocompleteBCS to provide stock information in SharePoint 2013: This .Net assembly BCS external system provides live, read only data on Dow Jones 30 stocks details from MSN money webservices.Blood Alcohol Measurement Tool: Az alkalmazás kijelzi a felhasználó véralkoholszint változását az elfogyasztott alkoholos italok függvényében.Busqueda Incremental con un TEXTBOX: Hola, aqui estoy de nuevo con un aporte mas para la comunidad, en muchos foros he visto que estan buscando como hacer una busqueda incremental en un TEXTBOX.CRM 2011: Reassign or Transfer Personal Views: This Project allows CRM Administrator to quickly transfer (i.e. assign) advanced find views from one CRM user to another CRM user. ctripITSM doc: this is a documentation share for ctripITSM projectet Sprint 3: etsprint3Finance App for Windows 8: This is an WinJS Windows 8 application that computes various financial metrics.gadgets: Windows Sidebar Gargetsjprj: jprjKerosene ORM: Kerosene is a self-adaptive and configuration-less ORM library, with a SQL syntax based on C# dynamics, WCF, and Entity Framework capabilities for POCO objects.Lobster: ?? ?? ?????????.My Google Map: MyGoogleMap est un outils de génération de carte. Onestop.Contrib.CustomAdmin: Onestop.Contrib.CustomAdmin is a Theme for Orchard CMS providing for changing the admin dashboard elements such as Title and Logo.Onestop.Contrib.Disqus: Onestop.Contrib.Disqus is an advanced commenting module for Orchard CMS that uses Disqus.Onestop.Contrib.LayoutSelector: Onestop.Contrib.LayoutSelector is a simple part for switching to different versions of Layout.cshtml when editing Orchard content items.Onestop.Contrib.Navigation: Onestop.Contrib.Navigation is an advanced Menu Management system designed for Orchard CMS. Onestop.Contrib.Seo: Onestop.Contrib.Seo is an advanced Search Engine Optimization module for Orchard CMSOnestop.Contrib.SlideShow: Onestop.Contrib.SlideShow is an advanced module for managing slide animations on a page.pf2012: Simple HTML5 game as PF2012 electronic greeting.PHP-2012: this is for php for schoolPruebaProyecto: Carmen Asencio AmbrosioPulawJS: MVC Platform for JavaScript. Inspired by Zend FrameworkRevolution Emulator: Habbo Hotel flash emulator targeting the .NET 4.5 VM, written in C#.Ruby Rookie: This Project is for learning Ruby purposesSISLOG_Proy2: SISLOGSkyShellEx: SkyShellEx allows to sync any folder to SkyDrive via a simple ShellExtension. The sync option appears on the context menu of folders where applicable. sosoft: Sosoft Project.C# WinForm.Include Alarm Clock.sound9: sound9testddgit09242012: dTFS Agile Work Item Rollover: This is a command line utility used to rollover incomplete work from one sprint to the next. The tool has both interactive and silent modes, allowing you to seTFS Deployment Studio: Helps deploying applications built using TFS to the servers where they belong.TreeView In-place Editing in MVVM: This project demonstrates a clean way of doing the in-place editing in the WPF TreeView controlUniSoft: Teste source controlValidation Framework for .NET: Framework for validation of method paramters and return values.WarOfDev: war of developer, make your coding interesting . Waterhouse: A C# console application that takes various text inputs and converts it to Morse Code by blinking the numlock indicator.Web Package Pro: in dev

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• Dapper and object validation/business rules enforcement

  - by Eugene

  This isn't really Dapper-specific, actually, as it relates to any XML-serializeable object.. but it came up when I was storing an object using Dapper. Anyways, say I have a user class. Normally, I'd do something like this: class User { public string SIN {get; private set;} public string DisplayName {get;set;} public User(string sin) { if (string.IsNullOrWhiteSpace(sin)) throw new ArgumentException("SIN must be specified"); this.SIN = sin; } } Since a SIN is required, I'd just create a constructor with a sin parameter, and make it read-only. However, with a Dapper (and probably any other ORM), I need to provide a parameterless constructor, and make all properties writeable. So now I have this: class User: IValidatableObject { public int Id { get; set; } public string SIN { get; set; } public string DisplayName { get; set; } public IEnumerable<ValidationResult> Validate(ValidationContext validationContext) { // implementation } } This seems.. can't really pick the word, a bad smell? A) I'm allowing to change properties that should not be changed ever after an object has been created (SIN, userid) B) Now I have to implement IValidatableObject or something like that to test those properties before updating them to db. So how do you go about it ?

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• Designing a Content-Based ETL Process with .NET and SFDC

  - by Patrick

  As my firm makes the transition to using SFDC as our main operational system, we've spun together a couple of SFDC portals where we can post customer-specific documents to be viewed at will. As such, we've had the need for pseudo-ETL applications to be implemented that are able to extract metadata from the documents our analysts generate internally (most are industry-standard PDFs, XML, or MS Office formats) and place in networked "queue" folders. From there, our applications scoop of the queued documents and upload them to the appropriate SFDC CRM Content Library along with some select pieces of metadata. I've mostly used DbAmp to broker communication with SFDC (DbAmp is a Linked Server provider that allows you to use SQL conventions to interact with your SFDC Org data). I've been able to create [console] applications in C# that work pretty well, and they're usually structured something like this: static void Main() { // Load parameters from app.config. // Get documents from queue. var files = someInterface.GetFiles(someFilterOrRegexPattern); foreach (var file in files) { // Extract metadata from the file. // Validate some attributes of the file; add any validation errors to an in-memory // structure (e.g. List<ValidationErrors>). if (isValid) { var fileData = File.ReadAllBytes(file); // Upload using some wrapper for an ORM or DAL someInterface.Upload(fileData, meta.Param1, meta.Param2, ...); } else { // Bounce the file } } // Report any validation errors (via message bus or SMTP or some such). } And that's pretty much it. Most of the time I wrap all these operations in a "Worker" class that takes the needed interfaces as constructor parameters. This approach has worked reasonably well, but I just get this feeling in my gut that there's something awful about it and would love some feedback. Is writing an ETL process as a C# Console app a bad idea? I'm also wondering if there are some design patterns that would be useful in this scenario that I'm clearly overlooking. Thanks in advance!

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• Which open source PHP project has the 'perfect' OOP design I can learn from?

  - by aditya menon

  I am a newbie to OOP, and I learn best by example. You could say this question is similar to Which Scala open source projects should I study to learn best coding practices - but in PHP. I have heard-tell that Symfony has the best 'architecture' (I will not pretend I know what that exactly means), as well as Doctrine ORM. Is it worth it to spend many months reading the source code of these projects, trying to deduce the patterns used and learning new tricks? I have seen equal number of web pages dissing and liking Zend's codebase (will provide links if deemed necessary). Do you know of any other project that would make any veteran OOP developer shed tears of joy? Please let me add that practicality and scope of use is not a concern at all here - I just want to do: Pick a project that has a codebase deemed awesome by devs way better and greater than me. Write code that achieves what the project does. Compare results and try to learn what I don't know. Basically, an academic interest codebase. Any recommendations please?

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• New database profiling support in ANTS Performance Profiler

  - by Ben Emmett

  In May last year, the ANTS Performance Profiler team added the ability to profile database requests your application makes to SQL Server or Oracle. The really cool thing is that you’re shown those requests in the application’s call tree, so you can see what .NET code caused those queries to run. It’s particularly helpful if you’re using an ORM which automagically generates and runs queries for you, but which doesn’t necessarily do it in the most efficient way possible. Now by popular demand, we’ve added support for profiling MySQL (or MariaDB) and PostgreSQL, so you can see queries run against those databases too. Some of you have also said that you’re using the Devart dotConnect data providers instead of the native .NET ones, so we’ve added support for those drivers too. Hope it helps! For the record, here’s a list of supported connectors (ones in bold are new): SQL Server .NET Framework Data Provider Devart dotConnect for SQL Server Oracle .NET Framework Data Provider Oracle Data Provider for .NET Devart dotConnect for Oracle MySQL / MariaDB MySQL Connector/Net Devart dotConnect for MySQL PostgreSQL Npgsql .NET Data Provider for PostgreSQL Devart dotConnect for PostgreSQL SQL Server Compact Edition .NET Framework Data Provider for SQL Server Compact Edition Devart dotConnect for SQL Server Pro Have we missed a connector or database which you’d find useful? Tell us about it in the comments or by emailing [email protected]. Ben

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• Where should SQL/DB Queries be encapsulated in a software system?

  - by Stephen Bennet

  I frequently write small applications (either web based or otherwise) that require heavy database usage. i've attempted various ways of handling where to put the actual sql queries (sort of ad-hoc ORM systems). These include: Models that build themselves up - and only allowing SQL to be inside of a model. A sort of factory style method where the models are built by a factory class that is allowed to know about SQL. A third entity that maps models based on their fields/keys into the database and generates SQL code on the fly based on this. Is there a common knowledge of which method is best? Or another way I have missed? Clearly a lot of it will be based on the context of the system itself, which for me is usually to produce lightweight tools or utility frameworks. In experimenting, I've never found any of them that feel intuitively "right" and not clunky, but I also do not want to go for a full framework such as Django or Ruby - both because the tools I create are in a variety of languages and because they usually do not warrant that level of surrounding footprint.

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• Brand New Annotations Support

  - by Ondrej Brejla

  Hi all! Today we would like to introduce you our brand new annotation support for NetBeans 7.2. The first thing which is different is the look of annotations in code completion. As you can see, there is a new annotation icon and an annotation type. Because we have a lot of modules with their own annotations, we differ them in code completion window by their type. We support annotations for: ApiGen (legacy PHPDoc annotations), PHPUnit, Doctrine 2 (ORM and ODM) and Symfony 2. Every annotation can be associated with some context. We recognize four of them: function, class/interface (type), method and field. It means that you will get just proper annotations for your class field as well as your global function. Do you have your own annotations? Or do you simply miss some? There is nothing hard to add it in there. We have a simple UI for adding your custom annotations! It's in Tools -> Options -> PHP -> Annotations. Here you can simply add, edit or delete your annotations. When you try to create new one, all fields are prefilled by some default values. So you really don't have to remember "how to use that crazy freemarker syntax". If you are satisfied with your new annotation, you can see it in a code completion window among other annotations. As you can see it has its own "Custom" type. That's all for today and as usual, please test it and if you find something strange, don't hesitate to file a new issue (component php, subcomponent Editor). Thanks.

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• How to use the unit of work and repository patterns in a service oriented enviroment

  - by A. Karimi

  I've created an application framework using the unit of work and repository patterns for it's data layer. Data consumer layers such as presentation depend on the data layer design. For example a CRUD abstract form has a dependency to a repository (IRepository). This architecture works like a charm in client/server environments (Ex. a WPF application and a SQL Server). But I'm looking for a good pattern to change or reuse this architecture for a service oriented environment. Of course I have some ideas: Idea 1: The "Adapter" design pattern Keep the current architecture and create a new unit of work and repository implementation which can work with a service instead of the ORM. Data layer consumers are loosely coupled to the data layer so it's possible but the problem is about the unit of work; I have to create a context which tracks the objects state at the client side and sends the changes to the server side on calling the "Commit" (Something that I think the RIA has done for Silverlight). Here the diagram: ----------- CLIENT----------- | ------------------ SERVER ---------------------- [ UI ] -> [ UoW/Repository ] ---> [ Web Services ] -> [ UoW/Repository ] -> [DB] Idea 2: Add another layer Add another layer (let say "local services" or "data provider"), then put it between the data layer (unit of work and repository) and the data consumer layers (like UI). Then I have to rewrite the consumer classes (CRUD and other classes which are dependent to IRepository) to depend on another interface. And the diagram: ----------------- CLIENT ------------------ | ------------------- SERVER --------------------- [ UI ] -> [ Local Services/Data Provider ] ---> [ Web Services ] -> [ UoW/Repository ] -> [DB] Please note that I have the local services layer on the current architecture but it doesn't expose the data layer functionality. In another word the UI layer can communicate with both of the data and local services layers whereas the local services layer also uses the data layer. | | | | | | | | ---> | Local Services | ---> | | | UI | | | | Data | | | | | | | ----------------------------> | |

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• Pattern for Accessing MySQL connection

  - by Dipan Mehta

  We have an application which is C++ trying to access MySQL database. There are several (about 5 or so) threads in the application (with Boost library for threading) and in each thread has a few objects, each of which is trying to access Database for its' own purpose. It has a simple ORM kind of model but that really is not an important factor here. There are three potential access patterns i can think of: There could be single connection object per application or thread and is shared between all (or group). The object needs to be thread safe and there will be contentions but MySQL will not be fired with too many connections. Every object could initiate connection on its own. The database needs to take care of concurrency (which i think MySQL can) and the design could be much simpler. There could be two possibilities here. a. either object keeps a persistent connection for its life OR b. object initiate connection as and when needed. To simplify the contention as in case of 1 and not to create too many sockets as in case of 2, we can have group/set based connections. So there could be there could be more than one connection (say N), each of this connection could be shared connection across M objects. Naturally, each of the pattern has different resource cost and would work under different constraints and objectives. What criteria should i use to choose the pattern of this for my own application? What are some of the advantages and disadvantages of each of these pattern over the other? Are there any other pattern which is better? PS: I have been through these questions: mysql, one connection vs multiple and MySQL with mutiple threads and processes But they don't quite answer exactly what i am trying to ask.

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• Is defining every method/state per object in a series of UML diagrams representative of MDA in general?

  - by Max

  I am currently working on a project where we use a framework that combines code generation and ORM together with UML to develop software. Methods are added to UML classes and are generated into partial classes where "stuff happens". For example, an UML class "Content" could have the method DeleteFromFileSystem(void). Which could be implemented like this: public partial class Content { public void DeleteFromFileSystem() { File.Delete(...); } } All methods are designed like this. Everything happens in these gargantuan logic-bomb domain classes. Is this how MDA or DDD or similar usually is done? For now my impression of MDA/DDD (which this has been called by higherups) is that it severely stunts my productivity (everything must be done The Way) and that it hinders maintenance work since all logic are roped, entrenched, interspersed into the mentioned gargantuan bombs. Please refrain from interpreting this as a rant - I am merely curious if this is typical MDA or some sort of extreme MDA UPDATE Concerning the example above, in my opinion Content shouldn't handle deleting itself as such. What if we change from local storage to Amazon S3, in that case we would have to reimplement this functionality scattered over multiple places instead of one single interface which we can provide a second implementation for.

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• Dynamic filter expressions in an OpenAccess LINQ query

  We had some support questions recently where our customers had the need to combine multiple smaller predicate expressions with either an OR or an AND  logical operators (these will be the || and && operators if you are using C#). And because the code from the answer that we sent to these customers is very interesting, and can easily be refactorred into something reusable, we decided to write this blog post. The key thing that one must know is that if you want your predicate to be translated by OpenAccess ORM to SQL and executed on the server you must have a LINQ Expression that is not compiled. So, let’s say that you have these smaller predicate expressions: Expression<Func<Customer, bool>> filter1 = c => c.City.StartsWith("S");Expression<Func<Customer, bool>> filter2 = c => c.City.StartsWith("M");Expression<Func<Customer, bool>> filter3 = c => c.ContactTitle == "Owner"; And ...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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• Designing Content-Based ETL Process with .NET and SFDC

  - by Patrick

  As my firm makes the transition to using SFDC as our main operational system, we've spun together a couple of SFDC portals where we can post customer-specific documents to be viewed at will. As such, we've had the need for pseudo-ETL applications to be implemented that are able to extract metadata from the documents our analysts generate internally (most are industry-standard PDFs, XML, or MS Office formats) and place in networked "queue" folders. From there, our applications scoop of the queued documents and upload them to the appropriate SFDC CRM Content Library along with some select pieces of metadata. I've mostly used DbAmp to broker communication with SFDC (DbAmp is a Linked Server provider that allows you to use SQL conventions to interact with your SFDC Org data). I've been able to create [console] applications in C# that work pretty well, and they're usually structured something like this: static void Main() { // Load parameters from app.config. // Get documents from queue. var files = someInterface.GetFiles(someFilterOrRegexPattern); foreach (var file in files) { // Extract metadata from the file. // Validate some attributes of the file; add any validation errors to an in-memory // structure (e.g. List<ValidationErrors>). if (isValid) { // Upload using some wrapper for an ORM an someInterface.Upload(meta.Param1, meta.Param2, ...); } else { // Bounce the file } } // Report any validation errors (via message bus or SMTP or some such). } And that's pretty much it. Most of the time I wrap all these operations in a "Worker" class that takes the needed interfaces as constructor parameters. This approach has worked reasonably well, but I just get this feeling in my gut that there's something awful about it and would love some feedback. Is writing an ETL process as a C# Console app a bad idea? I'm also wondering if there are some design patterns that would be useful in this scenario that I'm clearly overlooking. Thanks in advance!

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• C++ Numerical Recipes &ndash; A New Adventure!

  - by JoshReuben

  I am about to embark on a great journey – over the next 6 weeks I plan to read through C++ Numerical Recipes 3rd edition http://amzn.to/YtdpkS I'll be reading this with an eye to C++ AMP, thinking about implementing the suitable subset (non-recursive, additive, commutative) to run on the GPU. APIs supporting HPC, GPGPU or MapReduce are all useful – providing you have the ability to choose the correct algorithm to leverage on them. I really think this is the most fascinating area of programming – a lot more exciting than LOB CRUD !!! When you think about it , everything is a function – we categorize & we extrapolate. As abstractions get higher & less leaky, sooner or later information systems programming will become a non-programmer task – you will be using WYSIWYG designers to build: GUIs MVVM service mapping & virtualization workflows ORM Entity relations In the data source SharePoint / LightSwitch are not there yet, but every iteration gets closer. For information workers, managed code is a race to the bottom. As MS futures are a bit shaky right now, the provider agnostic nature & higher barriers of entry of both C++ & Numerical Analysis seem like a rational choice to me. Its also fascinating – stepping outside the box. This is not the first time I've delved into numerical analysis. 6 months ago I read Numerical methods with Applications, which can be found for free online: http://nm.mathforcollege.com/ 2 years ago I learned the .NET Extreme Optimization library www.extremeoptimization.com – not bad 2.5 years ago I read Schaums Numerical Analysis book http://amzn.to/V5yuLI - not an easy read, as topics jump back & forth across chapters: 3 years ago I read Practical Numerical Methods with C# http://amzn.to/V5yCL9 (which is a toy learning language for this kind of stuff) I also read through AI a Modern Approach 3rd edition END to END http://amzn.to/V5yQSp - this took me a few years but was the most rewarding experience. I'll post progress updates – see you on the other side !

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• CodePlex Daily Summary for Tuesday, August 05, 2014

  CodePlex Daily Summary for Tuesday, August 05, 2014Popular ReleasesGMare: GMare Beta 1.3: Fixed: Sprites not being read inLib.Web.Mvc & Yet another developer blog: Lib.Web.Mvc 6.4.2: Lib.Web.Mvc is a library which contains some helper classes for ASP.NET MVC such as strongly typed jqGrid helper, XSL transformation HtmlHelper/ActionResult, FileResult with range request support, custom attributes and more. Release contains: Lib.Web.Mvc.dll with xml documentation file Standalone documentation in chm file and change log Library source code Sample application for strongly typed jqGrid helper is available here. Sample application for XSL transformation HtmlHelper/ActionRe...Virto Commerce Enterprise Open Source eCommerce Platform (asp.net mvc): Virto Commerce 1.11: Virto Commerce Community Edition version 1.11. To install the SDK package, please refer to SDK getting started documentation To configure source code package, please refer to Source code getting started documentation This release includes many bug fixes and minor improvements. More details about this release can be found on our blog at http://blog.virtocommerce.com.Json.NET: Json.NET 6.0 Release 4: New feature - Added Merge to LINQ to JSON New feature - Added JValue.CreateNull and JValue.CreateUndefined New feature - Added Windows Phone 8.1 support to .NET 4.0 portable assembly New feature - Added OverrideCreator to JsonObjectContract New feature - Added support for overriding the creation of interfaces and abstract types New feature - Added support for reading UUID BSON binary values as a Guid New feature - Added MetadataPropertyHandling.Ignore New feature - Improv...Aitso-a platform for spatial optimization and based on artificial immune systems: Aitso_0.14.08.01: Aitso0.14.08.01Installer.zipVidCoder: 1.5.24 Beta: Added NL-Means denoiser. Updated HandBrake core to SVN 6254. Added extra error handling to DVD player code to avoid a crash when the player was moved.EasyMR: v1.0: 1 ????????? 2 ????????? 3 ??????? ????????????????????，???????????????，???????????PowerShell App Deployment Toolkit: PowerShell App Deployment Toolkit v3.1.5: *Added Send-Keys function to send a sequence of keys to an application window (Thanks to mmashwani) *Added 3 optimization/stability improvements to Execute-Process following MS best practice (Thanks to mmashwani) *Fixed issue where Execute-MSI did not use value from XML file for uninstall but instead ran all uninstalls silently by default *Fixed error on 1641 exit code (should be a success like 3010) *Fixed issue with error handling in Invoke-SCCMTask *Fixed issue with deferral dates where th...Facebook Graph Toolkit: Facebook Graph Toolkit 5.0.493: updated to Graph Api v2.0 updated class definitions according to latest documentation fixed a potential memory leak causing socket exhaustion LINQ to FQL simplified usage performance improvement added missing constructorsCrashReporter.NET : Exception reporting library for C# and VB.NET: CrashReporter.NET 1.4: Added French, Italian, German, Russian and Spanish translation. Added DeveloperMessage field so developers can send value of variables or other details they want along with crash report. Fixed bug where subject of crash report email was affected by translation. Fixed bug where extension is not added in SaveFileDialog while saving crash report.AutoUpdater.NET : Auto update library for VB.NET and C# Developer: AutoUpdater.NET 1.3: Fixed problem in DownloadUpdateDialog where download continues even if you close the dialog. Added support for new url field for 64 bit application setup. AutoUpdater.NET will decide which download url to use by looking at the value of IntPtr.Size. Added German translation provided by Rene Kannegiesser. Now developer can handle update logic herself using event suggested by ricorx7. Added italian translation provided by Gianluca Mariani. Fixed bug that prevents Application from exiti...Windows Embedded Board Support Package for BeagleBone: WEC2013 Beaglebone Black 03.02.00: Demo image. Runs on BeagleBone White and Black. On BeagleBone Black works with uSD or eMMC based images. XAML support added. SDK and demo tests included. New SDK refresh (uninstall old version first) IoT M2MQTT client built in. Built and maintained in the U.S.A.!Essence#: Philemon-3 (Alpha Build 19): The Philemon-3 release corrects a problem with the script of the NSIS installation program generator used to build the installer for the previous release. That issue could have been addressed by simply fixing the script and then regenerating the installation program, but a) it was judged to be less work to create a new release based on the current development code, and b) a new release does a better job of communicating the fact that the installation program for the previous release is broken...SEToolbox: SEToolbox 01.041.012 Release 1: Added voxel material textures to read in with mods. Fixed missing texture replacements for mods. Fixed rounding issue in raytrace code. Fixed repair issue with corrupt checkpoint file. Fixed issue with updated SE binaries 01.041.012 using new container configuration.Continuous Affect Rating and Media Annotation: CARMA v6.02: Compiled as v6.02 for MCR 8.3 (2014a) 32-bit Windows version Ratings will now only be saved for full seconds (e.g., a 90.2s video will now yield 90 ratings instead of 91 ratings). This should be more transparent to users and ensure consistency in the number of ratings output by different computers. Separated the XLS and XLSX output formats in the save file drop-down box. This should be more transparent to users than having to add the appropriate extension.Magick.NET: Magick.NET 6.8.9.601: Magick.NET linked with ImageMagick 6.8.9.6 Breaking changes: - Changed arguments for the Map method of MagickImage. - QuantizeSettings uses Riemersma by default.Wallpapr: Wallpapr 1.7: Fixed the "Prohibited" message (Flickr upgraded their API to SSL-only).DbEntry.Net (Leafing Framework): DbEntry.Net 4.2: DbEntry.Net is a lightweight Object Relational Mapping (ORM) database access compnent for .Net 4.0+. It has clearly and easily programing interface for ORM and sql directly, and supoorted Access, Sql Server, MySql, SQLite, Firebird, PostgreSQL and Oracle. It also provide a Ruby On Rails style MVC framework. Asp.Net DataSource and a simple IoC. DbEntry.Net.v4.2.Setup.zip include the setup package. DbEntry.Net.v4.2.Src.zip include source files and unit tests. DbEntry.Net.v4.2.Samples.zip ...Azure Storage Explorer: Azure Storage Explorer 6 Preview 1: Welcome to Azure Storage Explorer 6 Preview 1 This is the first release of the latest Azure Storage Explorer, code-named Phoenix. What's New?Here are some important things to know about version 6: Open Source Now being run as a full open source project. Full source code on CodePlex. Collaboration encouraged! Updated Code Base Brand-new code base (WPF/C#/.NET 4.5) Visual Studio 2013 solution (previously VS2010) Uses the Task Parallel Library (TPL) for asynchronous background operat...Wsus Package Publisher: release v1.3.1407.29: Updated WPP to recognize the very latest console version. Some files was missing into the latest release of WPP which lead to crash when trying to make a custom update. Add a workaround to avoid clipboard modification when double-clicking on a label when creating a custom update. Add the ability to publish detectoids. (This feature is still in a BETA phase. Packages relying on these detectoids to determine which computers need to be updated, may apply to all computers).New ProjectsAPS - Folha de Pagamento: Folha de PagamentoCIS470 Metrics Tracking: A data driven application designed to display various project progress metrics and reports based off of data. CIS470 Metrics Tracking DeVry Capstone project.Excel Converter: A great tools to convert MS excel to PDF and vice verse. We plan support both Window and Web version.FreightSoft: A Web Based Shipping and Freight Management SystemGoogle .Net API: Dot Net warp for Google API Services. API Demo, documentation, simple useful tools. Welcome to join us make more google API works on Dot Net World. Google Driver downloader: A free tool to bulk download file from google driver to local box.Omniprogram: OmniprogramOnline OCR: A free to OCR via google APIOnline Resume Parsing Using Aspose.Words for .NET: Online Resume Parsing Using Aspose.Words for .NET. PDF Text Searcher: This application searches for a word from the PDF file name inside the PDF itself.PEIN Framework: A collection of day to day required libraries.Public Components: Public Components, by Danny VarodRole Based View for Microsoft Dynamic CRM 2011 & 2013: Allow admin to configure entity's view based on role.scmactivitytfs: Test project to play with Team Foundation Server.Selfpub.CrmSolution: Tram-pam-pamWindGE: WindGE????DirectX11??????3D???????，????????????????????，???WPF???????。yao's project: a project for personal study

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• Strategies for managUse of types in Python

  - by dave

  I'm a long time programmer in C# but have been coding in Python for the past year. One of the big hurdles for me was the lack of type definitions for variables and parameters. Whereas I totally get the idea of duck typing, I do find it frustrating that I can't tell the type of a variable just by looking at it. This is an issue when you look at someone else's code where they've used ambiguous names for method parameters (see edit below). In a few cases, I've added asserts to ensure parameters comply with an expected type but this goes against the whole duck typing thing. On some methods, I'll document the expected type of parameters (eg: list of user objects), but even this seems to go against the idea of just using an object and let the runtime deal with exceptions. What strategies do you use to avoid typing problems in Python? Edit: Example of the parameter naming issues: If our code base we have a task object (ORM object) and a task_obj object (higher level object that embeds a task). Needless to say, many methods accept a parameter named 'task'. The method might expect a task or a task_obj or some other construct such as a dictionary of task properties - it is not clear. It is them up to be to look at how that parameter is used in order to work out what the method expects.

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• Alternatives to Pessimistic Locking in Cluster Applications

  - by amphibient

  I am researching alternatives to database-level pessimistic locking to achieve transaction isolation in a cluster of Java applications going against the same database. Synchronizing concurrent access in the application tier is clearly not a solution in the present configuration because the same database transaction can be invoked from multiple JVMs concurrently. Currently, we are subject to occasional race conditions which, due to the optimistic locking we have in place via Hibernate, cause a StaleObjectStateException exception and data loss. I have a moderately large transaction within the scope of my refactoring project. Let's describe it as updating one top-level table row and then making various related inserts and/or updates to several of its child entities. I would like to insure exclusive access to the top-level table row and all of the children to be affected but I would like to stay away from pessimistic locking at the database level for performance reasons mostly. We use Hibernate for ORM. Does it make sense to start a single (perhaps synchronous) message queue application into which this method could be moved to insure synchronized access as opposed to each cluster node using its own, which is a clear race condition hazard? I am mentioning this approach even though I am not confident in it because both the top-level table row and its children could also be updated from other system calls, not just the mentioned transaction. So I am seeking to design a solution where the top-level table row and its children will all somehow be pseudo-locked (exclusive transaction isolation) but at the application and not the database level. I am open to ideas and suggestions, I understand this is not a very cut and dried challenge.

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• Database and query to store and retreive friend list [migrated]

  - by amr Kamboj

  I am developing a module in website to save and retreive friend list. I am using Zend Framework and for DB handling I am using Doctrine(ORM). There are two models: 1) users that stores all the users 2) my_friends that stores the friend list (that is refference table with M:M relation of user) the structure of my_friends is following ...id..........user_id............friend_id........approved.... ...10.........20 ..................25...................1.......... ...10.........21 ..................25...................1.......... ...10.........22 ..................30...................1.......... ...10.........25 ..................30...................1.......... The Doctrine query to retreive friend list id follwing $friends = Doctrine_Query::create()->from('my_friends as mf') ->leftJoin('mf.users as friend') ->where("mf.user_id = 25") ->andWhere("mf.approved = 1"); Suppose I am viewing the user no.- 25. With this query I am only getting the user no.- 30. where as user no.- 25 is also approved friend of user no.- 20 and 21. Please guide me, what should be the query to find all friend and is there any need to change the DB structure.

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• Is there a canonical source supporting "all-surrogates"?

  - by user61852

  Background The "all-PK-must-be-surrogates" approach is not present in Codd's Relational Model or any SQL Standard (ANSI, ISO or other). Canonical books seems to elude this restrictions too. Oracle's own data dictionary scheme uses natural keys in some tables and surrogate keys in other tables. I mention this because these people must know a thing or two about RDBMS design. PPDM (Professional Petroleum Data Management Association) recommend the same canonical books do: Use surrogate keys as primary keys when: There are no natural or business keys Natural or business keys are bad ( change often ) The value of natural or business key is not known at the time of inserting record Multicolumn natural keys ( usually several FK ) exceed three columns, which makes joins too verbose. Also I have not found canonical source that says natural keys need to be immutable. All I find is that they need to be very estable, i.e need to be changed only in very rare ocassions, if ever. I mention PPDM because these people must know a thing or two about RDBMS design too. The origins of the "all-surrogates" approach seems to come from recommendations from some ORM frameworks. It's true that the approach allows for rapid database modeling by not having to do much business analysis, but at the expense of maintainability and readability of the SQL code. Much prevision is made for something that may or may not happen in the future ( the natural PK changed so we will have to use the RDBMS cascade update funtionality ) at the expense of day-to-day task like having to join more tables in every query and having to write code for importing data between databases, an otherwise very strightfoward procedure (due to the need to avoid PK colisions and having to create stage/equivalence tables beforehand ). Other argument is that indexes based on integers are faster, but that has to be supported with benchmarks. Obviously, long, varying varchars are not good for PK. But indexes based on short, fix-length varchar are almost as fast as integers. The questions - Is there any canonical source that supports the "all-PK-must-be-surrogates" approach ? - Has Codd's relational model been superceded by a newer relational model ?

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• Service layer coupling

  - by Justin

  I am working on writing a service layer for an order system in php. It's the typical scenario, you have an Order that can have multiple Line Items. So lets say a request is received to store a line item with pictures and comments. I might receive a json request such as { 'type': 'Bike', 'color': 'Red', 'commentIds': [3193,3194] 'attachmentIds': [123,413] } My idea was to have a Service_LineItem_Bike class that knows how to take the json data and store an entity for a bike. My question is, the Service_LineItem class now needs to fetch comments and file attachments, and store the relationships. Service_LineItem seems like it should interact with a Service_Comment and a Service_FileUpload. Should instances of these two other services be instantiated and passed to the Service_LineItem constructor,or set by getters and setters? Dependency injection seems like the right solution, allowing a service access to a 'service fetching helper' seems wrong, and this should stay at the application level. I am using Doctrine 2 as a ORM, and I can technically write a dql query inside Service_LineItem to fetch the comments and file uploads necessary for the association, but this seems like it would have a tighter coupling, rather then leaving this up to the right service object.

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• I need an approach to the problem of preventing inserting duplicate records into the database

  - by Maurice

  Apologies is this question is asked on the incorrect "stack" A webservice that I call returns a list of data. The data from the webservice is updated periodically, so a call to the webservice done in one hour could return the same data as a call done in an hour. Also, the data is returned based on a start and end date. We have multiple users that can run the webservice search, and duplicate data is most likely to be returned (especially for historical data). However I don't want to insert this duplicate data in the database. I've created a db table in which the data is stored (most important columns are) Id int autoincrement PK Date date not null --The date to which the data set belongs. LastUpdate date not null --The date the data set was last updated. UserName varchar(50) --The name of the user doing the search. I use sql server 2008 express with c# 4.0 and visual studio 2010. Entity Framework is used as the ORM. If stored procedures could be avoided in the proposed solution, then that will be a plus. Another way of looking interpreting what I'm asking a solution for is as follows: I have a million unique records in my table. A user does a new search. The search results from the user contains around 300k of the data that is already in the db. An efficient solution to finding an inserting only the unique records is needed.

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• Strategies for managing use of types in Python

  - by dave

  I'm a long time programmer in C# but have been coding in Python for the past year. One of the big hurdles for me was the lack of type definitions for variables and parameters. Whereas I totally get the idea of duck typing, I do find it frustrating that I can't tell the type of a variable just by looking at it. This is an issue when you look at someone else's code where they've used ambiguous names for method parameters (see edit below). In a few cases, I've added asserts to ensure parameters comply with an expected type but this goes against the whole duck typing thing. On some methods, I'll document the expected type of parameters (eg: list of user objects), but even this seems to go against the idea of just using an object and let the runtime deal with exceptions. What strategies do you use to avoid typing problems in Python? Edit: Example of the parameter naming issues: If our code base we have a task object (ORM object) and a task_obj object (higher level object that embeds a task). Needless to say, many methods accept a parameter named 'task'. The method might expect a task or a task_obj or some other construct such as a dictionary of task properties - it is not clear. It is them up to be to look at how that parameter is used in order to work out what the method expects.

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• How to handle monetary values in PHP and MySql?

  - by Songo

  I've inherited a huge pile of legacy code written in PHP on top of a MySQL database. The thing I noticed is that the application uses doubles for storage and manipulation of data. Now I came across of numerous posts mentioning how double are not suited for monetary operations because of the rounding errors. However, I have yet to come across a complete solution to how monetary values should be handled in PHP code and stored in a MySQL database. Is there a best practice when it comes to handling money specifically in PHP? Things I'm looking for are: How should the data be stored in the database? column type? size? How should the data be handling in normal addition, subtraction. multiplication or division? When should I round the values? How much rounding is acceptable if any? Is there a difference between handling large monetary values and low ones? Note: A VERY simplified sample code of how I might encounter money values in everyday life: $a= $_POST['price_in_dollars']; //-->(ex: 25.06) will be read as a string should it be cast to double? $b= $_POST['discount_rate'];//-->(ex: 0.35) value will always be less than 1 $valueToBeStored= $a * $b; //--> any hint here is welcomed $valueFromDatabase= $row['price']; //--> price column in database could be double, decimal,...etc. $priceToPrint=$valueFromDatabase * 0.25; //again cast needed or not? I hope you use this sample code as a means to bring out more use cases and not to take it literally of course. Bonus Question If I'm to use an ORM such as Doctrine or PROPEL, how different will it be to use money in my code.

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• Two components offering the same functionality, required by different dependencies

  - by kander

  I'm building an application in PHP, using Zend Framework 1 and Doctrine2 as the ORM layer. All is going well. Now, I happened to notice that both ZF1 and Doctrine2 come with, and rely on, their own caching implementation. I've evaluated both, and while each has its own pro's and cons, neither of them stand out as superior to the other for my simple needs. Both libraries also seem to be written against their respective interfaces, not their implementations. Reasons why I feel this is an issue is that during the bootstrapping of my application, I have to configure two caching drivers - each with its own syntax. A mismatch is easily created this way, and it feels inefficient to set up two connections to the caching backend because of this. I'm trying to determine what the best way forward is, and would welcome any insights you may be able to offer. What I've thought up so far are four options: Do nothing, accept that two classes offering caching functionality are present. Create a Facade class to stick Zend's interface onto Doctrine's caching implementation. Option 2, the other way around - create a Facade to map Doctrine's interface on a Zend Framework backend. Use multiple-interface-inheritance to create one interface to rule them all, and pray that there aren't any overlaps (ie: if both have a "save" method, they'll need to accept params in the same order due to PHP's lack of proper polymorphism). What option is best, or is there a "None of the above" variant that I'm not aware of?

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• Creating my own PHP framework

  - by onlineapplab.com

  Disclaimer: I don't want to start any flame war so there will not be no name of any framework mentioned. I've been using quite many from the existing PHP frameworks and my experience in each case was similar: everything is nice a the beginning but in the moment you require something non standard you get into lot of problems to fix otherwise simple issues. In case of frameworks following the MVC design pattern there are some issues with the implementation of each layer for example there is a lot of codding used for model and data access with using ORM and presentation is not much more than pure phtml. Some frameworks use their own wrappers for existing PHP functionality and in some cases severely limiting original functionality. Depending on framework you can have additional problems like lack of documentation, slow or non existent development cycle and last but not least speed. While ago I made my own framework which while doing it's job and being used for few different applications after couple of years more of experience with PHP doesn't seem to be perfect piece of codding. I could write my own framework and use additional experience I've gathered during these years to make it better on the other hand I'm aware that there is quite many better programmers working on creating/upgrading existing frameworks. So does it make at all nay sense to write my own PHP framework if there is so many possibilities to choose from?

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• Inheritance Mapping Strategies with Entity Framework Code First CTP5: Part 3 – Table per Concrete Type (TPC) and Choosing Strategy Guidelines

  - by mortezam

  This is the third (and last) post in a series that explains different approaches to map an inheritance hierarchy with EF Code First. I've described these strategies in previous posts: Part 1 – Table per Hierarchy (TPH) Part 2 – Table per Type (TPT)In today’s blog post I am going to discuss Table per Concrete Type (TPC) which completes the inheritance mapping strategies supported by EF Code First. At the end of this post I will provide some guidelines to choose an inheritance strategy mainly based on what we've learned in this series. TPC and Entity Framework in the Past Table per Concrete type is somehow the simplest approach suggested, yet using TPC with EF is one of those concepts that has not been covered very well so far and I've seen in some resources that it was even discouraged. The reason for that is just because Entity Data Model Designer in VS2010 doesn't support TPC (even though the EF runtime does). That basically means if you are following EF's Database-First or Model-First approaches then configuring TPC requires manually writing XML in the EDMX file which is not considered to be a fun practice. Well, no more. You'll see that with Code First, creating TPC is perfectly possible with fluent API just like other strategies and you don't need to avoid TPC due to the lack of designer support as you would probably do in other EF approaches. Table per Concrete Type (TPC)In Table per Concrete type (aka Table per Concrete class) we use exactly one table for each (nonabstract) class. All properties of a class, including inherited properties, can be mapped to columns of this table, as shown in the following figure: As you can see, the SQL schema is not aware of the inheritance; effectively, we’ve mapped two unrelated tables to a more expressive class structure. If the base class was concrete, then an additional table would be needed to hold instances of that class. I have to emphasize that there is no relationship between the database tables, except for the fact that they share some similar columns. TPC Implementation in Code First Just like the TPT implementation, we need to specify a separate table for each of the subclasses. We also need to tell Code First that we want all of the inherited properties to be mapped as part of this table. In CTP5, there is a new helper method on EntityMappingConfiguration class called MapInheritedProperties that exactly does this for us. Here is the complete object model as well as the fluent API to create a TPC mapping: public abstract class BillingDetail {     public int BillingDetailId { get; set; }     public string Owner { get; set; }     public string Number { get; set; } }          public class BankAccount : BillingDetail {     public string BankName { get; set; }     public string Swift { get; set; } }          public class CreditCard : BillingDetail {     public int CardType { get; set; }     public string ExpiryMonth { get; set; }     public string ExpiryYear { get; set; } }      public class InheritanceMappingContext : DbContext {     public DbSet<BillingDetail> BillingDetails { get; set; }              protected override void OnModelCreating(ModelBuilder modelBuilder)     {         modelBuilder.Entity<BankAccount>().Map(m =>         {             m.MapInheritedProperties();             m.ToTable("BankAccounts");         });         modelBuilder.Entity<CreditCard>().Map(m =>         {             m.MapInheritedProperties();             m.ToTable("CreditCards");         });                 } } The Importance of EntityMappingConfiguration ClassAs a side note, it worth mentioning that EntityMappingConfiguration class turns out to be a key type for inheritance mapping in Code First. Here is an snapshot of this class: namespace System.Data.Entity.ModelConfiguration.Configuration.Mapping {     public class EntityMappingConfiguration<TEntityType> where TEntityType : class     {         public ValueConditionConfiguration Requires(string discriminator);         public void ToTable(string tableName);         public void MapInheritedProperties();     } } As you have seen so far, we used its Requires method to customize TPH. We also used its ToTable method to create a TPT and now we are using its MapInheritedProperties along with ToTable method to create our TPC mapping. TPC Configuration is Not Done Yet!We are not quite done with our TPC configuration and there is more into this story even though the fluent API we saw perfectly created a TPC mapping for us in the database. To see why, let's start working with our object model. For example, the following code creates two new objects of BankAccount and CreditCard types and tries to add them to the database: using (var context = new InheritanceMappingContext()) {     BankAccount bankAccount = new BankAccount();     CreditCard creditCard = new CreditCard() { CardType = 1 };                      context.BillingDetails.Add(bankAccount);     context.BillingDetails.Add(creditCard);     context.SaveChanges(); } Running this code throws an InvalidOperationException with this message: The changes to the database were committed successfully, but an error occurred while updating the object context. The ObjectContext might be in an inconsistent state. Inner exception message: AcceptChanges cannot continue because the object's key values conflict with another object in the ObjectStateManager. Make sure that the key values are unique before calling AcceptChanges. The reason we got this exception is because DbContext.SaveChanges() internally invokes SaveChanges method of its internal ObjectContext. ObjectContext's SaveChanges method on its turn by default calls AcceptAllChanges after it has performed the database modifications. AcceptAllChanges method merely iterates over all entries in ObjectStateManager and invokes AcceptChanges on each of them. Since the entities are in Added state, AcceptChanges method replaces their temporary EntityKey with a regular EntityKey based on the primary key values (i.e. BillingDetailId) that come back from the database and that's where the problem occurs since both the entities have been assigned the same value for their primary key by the database (i.e. on both BillingDetailId = 1) and the problem is that ObjectStateManager cannot track objects of the same type (i.e. BillingDetail) with the same EntityKey value hence it throws. If you take a closer look at the TPC's SQL schema above, you'll see why the database generated the same values for the primary keys: the BillingDetailId column in both BankAccounts and CreditCards table has been marked as identity. How to Solve The Identity Problem in TPC As you saw, using SQL Server’s int identity columns doesn't work very well together with TPC since there will be duplicate entity keys when inserting in subclasses tables with all having the same identity seed. Therefore, to solve this, either a spread seed (where each table has its own initial seed value) will be needed, or a mechanism other than SQL Server’s int identity should be used. Some other RDBMSes have other mechanisms allowing a sequence (identity) to be shared by multiple tables, and something similar can be achieved with GUID keys in SQL Server. While using GUID keys, or int identity keys with different starting seeds will solve the problem but yet another solution would be to completely switch off identity on the primary key property. As a result, we need to take the responsibility of providing unique keys when inserting records to the database. We will go with this solution since it works regardless of which database engine is used. Switching Off Identity in Code First We can switch off identity simply by placing DatabaseGenerated attribute on the primary key property and pass DatabaseGenerationOption.None to its constructor. DatabaseGenerated attribute is a new data annotation which has been added to System.ComponentModel.DataAnnotations namespace in CTP5: public abstract class BillingDetail {     [DatabaseGenerated(DatabaseGenerationOption.None)]     public int BillingDetailId { get; set; }     public string Owner { get; set; }     public string Number { get; set; } } As always, we can achieve the same result by using fluent API, if you prefer that: modelBuilder.Entity<BillingDetail>()             .Property(p => p.BillingDetailId)             .HasDatabaseGenerationOption(DatabaseGenerationOption.None); Working With The Object Model Our TPC mapping is ready and we can try adding new records to the database. But, like I said, now we need to take care of providing unique keys when creating new objects: using (var context = new InheritanceMappingContext()) {     BankAccount bankAccount = new BankAccount()      {          BillingDetailId = 1                          };     CreditCard creditCard = new CreditCard()      {          BillingDetailId = 2,         CardType = 1     };                      context.BillingDetails.Add(bankAccount);     context.BillingDetails.Add(creditCard);     context.SaveChanges(); } Polymorphic Associations with TPC is Problematic The main problem with this approach is that it doesn’t support Polymorphic Associations very well. After all, in the database, associations are represented as foreign key relationships and in TPC, the subclasses are all mapped to different tables so a polymorphic association to their base class (abstract BillingDetail in our example) cannot be represented as a simple foreign key relationship. For example, consider the the domain model we introduced here where User has a polymorphic association with BillingDetail. This would be problematic in our TPC Schema, because if User has a many-to-one relationship with BillingDetail, the Users table would need a single foreign key column, which would have to refer both concrete subclass tables. This isn’t possible with regular foreign key constraints. Schema Evolution with TPC is Complex A further conceptual problem with this mapping strategy is that several different columns, of different tables, share exactly the same semantics. This makes schema evolution more complex. For example, a change to a base class property results in changes to multiple columns. It also makes it much more difficult to implement database integrity constraints that apply to all subclasses. Generated SQLLet's examine SQL output for polymorphic queries in TPC mapping. For example, consider this polymorphic query for all BillingDetails and the resulting SQL statements that being executed in the database: var query = from b in context.BillingDetails select b; Just like the SQL query generated by TPT mapping, the CASE statements that you see in the beginning of the query is merely to ensure columns that are irrelevant for a particular row have NULL values in the returning flattened table. (e.g. BankName for a row that represents a CreditCard type). TPC's SQL Queries are Union Based As you can see in the above screenshot, the first SELECT uses a FROM-clause subquery (which is selected with a red rectangle) to retrieve all instances of BillingDetails from all concrete class tables. The tables are combined with a UNION operator, and a literal (in this case, 0 and 1) is inserted into the intermediate result; (look at the lines highlighted in yellow.) EF reads this to instantiate the correct class given the data from a particular row. A union requires that the queries that are combined, project over the same columns; hence, EF has to pad and fill up nonexistent columns with NULL. This query will really perform well since here we can let the database optimizer find the best execution plan to combine rows from several tables. There is also no Joins involved so it has a better performance than the SQL queries generated by TPT where a Join is required between the base and subclasses tables. Choosing Strategy GuidelinesBefore we get into this discussion, I want to emphasize that there is no one single "best strategy fits all scenarios" exists. As you saw, each of the approaches have their own advantages and drawbacks. Here are some rules of thumb to identify the best strategy in a particular scenario: If you don’t require polymorphic associations or queries, lean toward TPC—in other words, if you never or rarely query for BillingDetails and you have no class that has an association to BillingDetail base class. I recommend TPC (only) for the top level of your class hierarchy, where polymorphism isn’t usually required, and when modification of the base class in the future is unlikely. If you do require polymorphic associations or queries, and subclasses declare relatively few properties (particularly if the main difference between subclasses is in their behavior), lean toward TPH. Your goal is to minimize the number of nullable columns and to convince yourself (and your DBA) that a denormalized schema won’t create problems in the long run. If you do require polymorphic associations or queries, and subclasses declare many properties (subclasses differ mainly by the data they hold), lean toward TPT. Or, depending on the width and depth of your inheritance hierarchy and the possible cost of joins versus unions, use TPC. By default, choose TPH only for simple problems. For more complex cases (or when you’re overruled by a data modeler insisting on the importance of nullability constraints and normalization), you should consider the TPT strategy. But at that point, ask yourself whether it may not be better to remodel inheritance as delegation in the object model (delegation is a way of making composition as powerful for reuse as inheritance). Complex inheritance is often best avoided for all sorts of reasons unrelated to persistence or ORM. EF acts as a buffer between the domain and relational models, but that doesn’t mean you can ignore persistence concerns when designing your classes. SummaryIn this series, we focused on one of the main structural aspect of the object/relational paradigm mismatch which is inheritance and discussed how EF solve this problem as an ORM solution. We learned about the three well-known inheritance mapping strategies and their implementations in EF Code First. Hopefully it gives you a better insight about the mapping of inheritance hierarchies as well as choosing the best strategy for your particular scenario. Happy New Year and Happy Code-Firsting! References ADO.NET team blog Java Persistence with Hibernate book a { color: #5A99FF; } a:visited { color: #5A99FF; } .title { padding-bottom: 5px; font-family: Segoe UI; font-size: 11pt; font-weight: bold; padding-top: 15px; } .code, .typeName { font-family: consolas; } .typeName { color: #2b91af; } .padTop5 { padding-top: 5px; } .padTop10 { padding-top: 10px; } .exception { background-color: #f0f0f0; font-style: italic; padding-bottom: 5px; padding-left: 5px; padding-top: 5px; padding-right: 5px; }

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