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  • Ruby on Rails Increment Counter in Model

    - by febs
    I'm attempting to increment a counter in my User table from another model. class Count < ActiveRecord::Base belongs_to :user after_create :update_count def update_count user = User.find(self.user_id) user.increment(:count) end end So when count is created the goal would be to increment a counter column for that user. Currently it refuses to get the user after creation and I get a nil error. I'm using devise for my Users Is this the right (best practice) place to do it? I had it working in the controllers, but wanted to clean it up. I'm very inexperienced with Model callbacks.

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  • How to model localized items

    - by tweir
    I'm currently designing a e-commerce solution. One of the primary requirements is for the store to support localized item details. The same store must be able to support multiple languages via the user's language selection and/or browser preference. I have two tables: Item (id, sku, price, ...) ItemDetails (item_id, language, title, ...) For each Item, there will be multiple rows corresponding to the item, where the (item_id,language) pair will be unique. I would like to model this as: class Item { public string sku; public double price; public ItemDetails Details; } Based on the user's session, I would like the items returned to have the Details object corresponds to the user's selected language (from their session). What are some approaches for representing this?

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  • How should I handle this Optimistic Concurrency error in this Entity Framework code, I have?

    - by Pure.Krome
    Hi folks, I have the following pseduo code in some Repository Pattern project that uses EF4. public void Delete(int someId) { // 1. Load the entity for that Id. If there is none, then null. // 2. If entity != null, then DeleteObject(..); } Pretty simple but I'm getting a run-time error:- ConcurrencyException: Store, Update, Insert or Delete statement affected an unexpected number of rows (0). Now, this is what is happening :- Two instances of EF4 are running inthe app at the same time. Instance A calls delete. Instance B calls delete a nano second later. Instance A loads the entity. Instance B also loads the entity. Instance A now deletes that entity - cool bananas. Instance B tries to delete the entity, but it's already gone. As such, the no-count or what not is 0, when it expected 1 .. or something like that. Basically, it figured out that the item it is suppose to delete, didn't delete (because it happened a split sec ago). I'm not sure if this is like a race-condition or something. Anyways, is there any tricks I can do here so the 2nd call doesn't crash? I could make it into a stored procedure.. but I'm hoping to avoid that right now. Any ideas? I'm wondering If it's possible to lock that row (and that row only) when the select is called ... forcing Instance B to wait until the row lock has been relased. By that time, the row is deleted, so when Instance B does it's select, the data is not there .. so it will never delete.

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  • How can I implement CRUD operations in a base class for an entity framework app?

    - by hminaya
    I'm working a simple EF/MVC app and I'm trying to implement some Repositories to handle my entities. I've set up a BaseObject Class and a IBaseRepository Interface to handle the most basic operations so I don't have to repeat myself each time: public abstract class BaseObject<T> { public XA.Model.Entities.XAEntities db; public BaseObject() { db = new Entities.XAEntities(); } public BaseObject(Entities.XAEntities cont) { db = cont; } public void Delete(T entity) { db.DeleteObject(entity); db.SaveChanges(); } public void Update(T entity) { db.AcceptAllChanges(); db.SaveChanges(); } } public interface IBaseRepository<T> { void Add(T entity); T GetById(int id); IQueryable<T> GetAll(); } But then I find myself having to implement 3 basic methods in every Repository ( Add, GetById & GetAll): public class AgencyRepository : Framework.BaseObject<Agency>, Framework.IBaseRepository<Agency> { public void Add(Agency entity) { db.Companies.AddObject(entity); db.SaveChanges(); } public Agency GetById(int id) { return db.Companies.OfType<Agency>().FirstOrDefault(x => x.Id == id); } public IQueryable<Agency> GetAll() { var agn = from a in db.Companies.OfType<Agency>() select a; return agn; } } How can I get these into my BaseObject Class so I won't run in conflict with DRY.

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  • Announcing the Release of Visual Studio 2013 and Great Improvements to ASP.NET and Entity Framework

    - by ScottGu
    Today we released VS 2013 and .NET 4.5.1. These releases include a ton of great improvements, and include some fantastic enhancements to ASP.NET and the Entity Framework.  You can download and start using them now. Below are details on a few of the great ASP.NET, Web Development, and Entity Framework improvements you can take advantage of with this release.  Please visit http://www.asp.net/vnext for additional release notes, documentation, and tutorials. One ASP.NET With the release of Visual Studio 2013, we have taken a step towards unifying the experience of using the different ASP.NET sub-frameworks (Web Forms, MVC, Web API, SignalR, etc), and you can now easily mix and match the different ASP.NET technologies you want to use within a single application. When you do a File-New Project with VS 2013 you’ll now see a single ASP.NET Project option: Selecting this project will bring up an additional dialog that allows you to start with a base project template, and then optionally add/remove the technologies you want to use in it.  For example, you could start with a Web Forms template and add Web API or Web Forms support for it, or create a MVC project and also enable Web Forms pages within it: This makes it easy for you to use any ASP.NET technology you want within your apps, and take advantage of any feature across the entire ASP.NET technology span. Richer Authentication Support The new “One ASP.NET” project dialog also includes a new Change Authentication button that, when pushed, enables you to easily change the authentication approach used by your applications – and makes it much easier to build secure applications that enable SSO from a variety of identity providers.  For example, when you start with the ASP.NET Web Forms or MVC templates you can easily add any of the following authentication options to the application: No Authentication Individual User Accounts (Single Sign-On support with FaceBook, Twitter, Google, and Microsoft ID – or Forms Auth with ASP.NET Membership) Organizational Accounts (Single Sign-On support with Windows Azure Active Directory ) Windows Authentication (Active Directory in an intranet application) The Windows Azure Active Directory support is particularly cool.  Last month we updated Windows Azure Active Directory so that developers can now easily create any number of Directories using it (for free and deployed within seconds).  It now takes only a few moments to enable single-sign-on support within your ASP.NET applications against these Windows Azure Active Directories.  Simply choose the “Organizational Accounts” radio button within the Change Authentication dialog and enter the name of your Windows Azure Active Directory to do this: This will automatically configure your ASP.NET application to use Windows Azure Active Directory and register the application with it.  Now when you run the app your users can easily and securely sign-in using their Active Directory credentials within it – regardless of where the application is hosted on the Internet. For more information about the new process for creating web projects, see Creating ASP.NET Web Projects in Visual Studio 2013. Responsive Project Templates with Bootstrap The new default project templates for ASP.NET Web Forms, MVC, Web API and SPA are built using Bootstrap. Bootstrap is an open source CSS framework that helps you build responsive websites which look great on different form factors such as mobile phones, tables and desktops. For example in a browser window the home page created by the MVC template looks like the following: When you resize the browser to a narrow window to see how it would like on a phone, you can notice how the contents gracefully wrap around and the horizontal top menu turns into an icon: When you click the menu-icon above it expands into a vertical menu – which enables a good navigation experience for small screen real-estate devices: We think Bootstrap will enable developers to build web applications that work even better on phones, tablets and other mobile devices – and enable you to easily build applications that can leverage the rich ecosystem of Bootstrap CSS templates already out there.  You can learn more about Bootstrap here. Visual Studio Web Tooling Improvements Visual Studio 2013 includes a new, much richer, HTML editor for Razor files and HTML files in web applications. The new HTML editor provides a single unified schema based on HTML5. It has automatic brace completion, jQuery UI and AngularJS attribute IntelliSense, attribute IntelliSense Grouping, and other great improvements. For example, typing “ng-“ on an HTML element will show the intellisense for AngularJS: This support for AngularJS, Knockout.js, Handlebars and other SPA technologies in this release of ASP.NET and VS 2013 makes it even easier to build rich client web applications: The screen shot below demonstrates how the HTML editor can also now inspect your page at design-time to determine all of the CSS classes that are available. In this case, the auto-completion list contains classes from Bootstrap’s CSS file. No more guessing at which Bootstrap element names you need to use: Visual Studio 2013 also comes with built-in support for both CoffeeScript and LESS editing support. The LESS editor comes with all the cool features from the CSS editor and has specific Intellisense for variables and mixins across all the LESS documents in the @import chain. Browser Link – SignalR channel between browser and Visual Studio The new Browser Link feature in VS 2013 lets you run your app within multiple browsers on your dev machine, connect them to Visual Studio, and simultaneously refresh all of them just by clicking a button in the toolbar. You can connect multiple browsers (including IE, FireFox, Chrome) to your development site, including mobile emulators, and click refresh to refresh all the browsers all at the same time.  This makes it much easier to easily develop/test against multiple browsers in parallel. Browser Link also exposes an API to enable developers to write Browser Link extensions.  By enabling developers to take advantage of the Browser Link API, it becomes possible to create very advanced scenarios that crosses boundaries between Visual Studio and any browser that’s connected to it. Web Essentials takes advantage of the API to create an integrated experience between Visual Studio and the browser’s developer tools, remote controlling mobile emulators and a lot more. You will see us take advantage of this support even more to enable really cool scenarios going forward. ASP.NET Scaffolding ASP.NET Scaffolding is a new code generation framework for ASP.NET Web applications. It makes it easy to add boilerplate code to your project that interacts with a data model. In previous versions of Visual Studio, scaffolding was limited to ASP.NET MVC projects. With Visual Studio 2013, you can now use scaffolding for any ASP.NET project, including Web Forms. When using scaffolding, we ensure that all required dependencies are automatically installed for you in the project. For example, if you start with an ASP.NET Web Forms project and then use scaffolding to add a Web API Controller, the required NuGet packages and references to enable Web API are added to your project automatically.  To do this, just choose the Add->New Scaffold Item context menu: Support for scaffolding async controllers uses the new async features from Entity Framework 6. ASP.NET Identity ASP.NET Identity is a new membership system for ASP.NET applications that we are introducing with this release. ASP.NET Identity makes it easy to integrate user-specific profile data with application data. ASP.NET Identity also allows you to choose the persistence model for user profiles in your application. You can store the data in a SQL Server database or another data store, including NoSQL data stores such as Windows Azure Storage Tables. ASP.NET Identity also supports Claims-based authentication, where the user’s identity is represented as a set of claims from a trusted issuer. Users can login by creating an account on the website using username and password, or they can login using social identity providers (such as Microsoft Account, Twitter, Facebook, Google) or using organizational accounts through Windows Azure Active Directory or Active Directory Federation Services (ADFS). To learn more about how to use ASP.NET Identity visit http://www.asp.net/identity.  ASP.NET Web API 2 ASP.NET Web API 2 has a bunch of great improvements including: Attribute routing ASP.NET Web API now supports attribute routing, thanks to a contribution by Tim McCall, the author of http://attributerouting.net. With attribute routing you can specify your Web API routes by annotating your actions and controllers like this: OAuth 2.0 support The Web API and Single Page Application project templates now support authorization using OAuth 2.0. OAuth 2.0 is a framework for authorizing client access to protected resources. It works for a variety of clients including browsers and mobile devices. OData Improvements ASP.NET Web API also now provides support for OData endpoints and enables support for both ATOM and JSON-light formats. With OData you get support for rich query semantics, paging, $metadata, CRUD operations, and custom actions over any data source. Below are some of the specific enhancements in ASP.NET Web API 2 OData. Support for $select, $expand, $batch, and $value Improved extensibility Type-less support Reuse an existing model OWIN Integration ASP.NET Web API now fully supports OWIN and can be run on any OWIN capable host. With OWIN integration, you can self-host Web API in your own process alongside other OWIN middleware, such as SignalR. For more information, see Use OWIN to Self-Host ASP.NET Web API. More Web API Improvements In addition to the features above there have been a host of other features in ASP.NET Web API, including CORS support Authentication Filters Filter Overrides Improved Unit Testability Portable ASP.NET Web API Client To learn more go to http://www.asp.net/web-api/ ASP.NET SignalR 2 ASP.NET SignalR is library for ASP.NET developers that dramatically simplifies the process of adding real-time web functionality to your applications. Real-time web functionality is the ability to have server-side code push content to connected clients instantly as it becomes available. SignalR 2.0 introduces a ton of great improvements. We’ve added support for Cross-Origin Resource Sharing (CORS) to SignalR 2.0. iOS and Android support for SignalR have also been added using the MonoTouch and MonoDroid components from the Xamarin library (for more information on how to use these additions, see the article Using Xamarin Components from the SignalR wiki). We’ve also added support for the Portable .NET Client in SignalR 2.0 and created a new self-hosting package. This change makes the setup process for SignalR much more consistent between web-hosted and self-hosted SignalR applications. To learn more go to http://www.asp.net/signalr. ASP.NET MVC 5 The ASP.NET MVC project templates integrate seamlessly with the new One ASP.NET experience and enable you to integrate all of the above ASP.NET Web API, SignalR and Identity improvements. You can also customize your MVC project and configure authentication using the One ASP.NET project creation wizard. The MVC templates have also been updated to use ASP.NET Identity and Bootstrap as well. An introductory tutorial to ASP.NET MVC 5 can be found at Getting Started with ASP.NET MVC 5. This release of ASP.NET MVC also supports several nice new MVC-specific features including: Authentication filters: These filters allow you to specify authentication logic per-action, per-controller or globally for all controllers. Attribute Routing: Attribute Routing allows you to define your routes on actions or controllers. To learn more go to http://www.asp.net/mvc Entity Framework 6 Improvements Visual Studio 2013 ships with Entity Framework 6, which bring a lot of great new features to the data access space: Async and Task<T> Support EF6’s new Async Query and Save support enables you to perform asynchronous data access and take advantage of the Task<T> support introduced in .NET 4.5 within data access scenarios.  This allows you to free up threads that might otherwise by blocked on data access requests, and enable them to be used to process other requests whilst you wait for the database engine to process operations. When the database server responds the thread will be re-queued within your ASP.NET application and execution will continue.  This enables you to easily write significantly more scalable server code. Here is an example ASP.NET WebAPI action that makes use of the new EF6 async query methods: Interception and Logging Interception and SQL logging allows you to view – or even change – every command that is sent to the database by Entity Framework. This includes a simple, human readable log – which is great for debugging – as well as some lower level building blocks that give you access to the command and results. Here is an example of wiring up the simple log to Debug in the constructor of an MVC controller: Custom Code-First Conventions The new Custom Code-First Conventions enable bulk configuration of a Code First model – reducing the amount of code you need to write and maintain. Conventions are great when your domain classes don’t match the Code First conventions. For example, the following convention configures all properties that are called ‘Key’ to be the primary key of the entity they belong to. This is different than the default Code First convention that expects Id or <type name>Id. Connection Resiliency The new Connection Resiliency feature in EF6 enables you to register an execution strategy to handle – and potentially retry – failed database operations. This is especially useful when deploying to cloud environments where dropped connections become more common as you traverse load balancers and distributed networks. EF6 includes a built-in execution strategy for SQL Azure that knows about retryable exception types and has some sensible – but overridable – defaults for the number of retries and time between retries when errors occur. Registering it is simple using the new Code-Based Configuration support: These are just some of the new features in EF6. You can visit the release notes section of the Entity Framework site for a complete list of new features. Microsoft OWIN Components Open Web Interface for .NET (OWIN) defines an open abstraction between .NET web servers and web applications, and the ASP.NET “Katana” project brings this abstraction to ASP.NET. OWIN decouples the web application from the server, making web applications host-agnostic. For example, you can host an OWIN-based web application in IIS or self-host it in a custom process. For more information about OWIN and Katana, see What's new in OWIN and Katana. Summary Today’s Visual Studio 2013, ASP.NET and Entity Framework release delivers some fantastic new features that streamline your web development lifecycle. These feature span from server framework to data access to tooling to client-side HTML development.  They also integrate some great open-source technology and contributions from our developer community. Download and start using them today! Scott P.S. In addition to blogging, I am also now using Twitter for quick updates and to share links. Follow me at: twitter.com/scottgu

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  • How Do You Actually Model Data?

    Since the 1970’s Developers, Analysts and DBAs have been able to represent concepts and relations in the form of data through the use of generic symbols.  But what is data modeling?  The first time I actually heard this term I could not understand why anyone would want to display a computer on a fashion show runway. Hey, what do you expect? At that time I was a freshman in community college, and obviously this was a long time ago.  I have since had the chance to learn what data modeling truly is through using it. Data modeling is a process of breaking down information and/or requirements in to common categories called objects. Once objects start being defined then relationships start to form based on dependencies found amongst other existing objects.  Currently, there are several tools on the market that help data designer actually map out objects and their relationships through the use of symbols and lines.  These diagrams allow for designs to be review from several perspectives so that designers can ensure that they have the optimal data design for their project and that the design is flexible enough to allow for potential changes and/or extension in the future. Additionally these basic models can always be further refined to show different levels of details depending on the target audience through the use of three different types of models. Conceptual Data Model(CDM)Conceptual Data Models include all key entities and relationships giving a viewer a high level understanding of attributes. Conceptual data model are created by gathering and analyzing information from various sources pertaining to a project during the typical planning phase of a project. Logical Data Model (LDM)Logical Data Models are conceptual data models that have been expanded to include implementation details pertaining to the data that it will store. Additionally, this model typically represents an origination’s business requirements and business rules by defining various attribute data types and relationships regarding each entity. This additional information can be directly translated to the Physical Data Model which reduces the actual time need to implement it. Physical Data Model(PDMs)Physical Data Model are transformed Logical Data Models that include the necessary tables, columns, relationships, database properties for the creation of a database. This model also allows for considerations regarding performance, indexing and denormalization that are applied through database rules, data integrity. Further expanding on why we actually use models in modern application/database development can be seen in the benefits that data modeling provides for data modelers and projects themselves, Benefits of Data Modeling according to Applied Information Science Abstraction that allows data designers remove concepts and ideas form hard facts in the form of data. This gives the data designers the ability to express general concepts and/or ideas in a generic form through the use of symbols to represent data items and the relationships between the items. Transparency through the use of data models allows complex ideas to be translated in to simple symbols so that the concept can be understood by all viewpoints and limits the amount of confusion and misunderstanding. Effectiveness in regards to tuning a model for acceptable performance while maintaining affordable operational costs. In addition it allows systems to be built on a solid foundation in terms of data. I shudder at the thought of a world without data modeling, think about it? Data is everywhere in our lives. Data modeling allows for optimizing a design for performance and the reduction of duplication. If one was to design a database without data modeling then I would think that the first things to get impacted would be database performance due to poorly designed database and there would be greater chances of unnecessary data duplication that would also play in to the excessive query times because unneeded records would need to be processed. You could say that a data designer designing a database is like a box of chocolates. You will never know what kind of database you will get until after it is built.

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  • RIA Services: Inserting multiple presentation-model objects

    - by nlawalker
    I'm sharing data via RIA services using a presentation model on top of LINQ to SQL classes. On the Silverlight client, I created a couple of new entities (album and artist), associated them with each other (by either adding the album to the artist's album collection, or setting the Artist property on the album - either one works), added them to the context, and submitted changes. On the server, I get two separate Insert calls - one for the album and one for the artist. These entitites are new so their ID values are both set to the default int value (0 - keep in mind that depending on my DB, this could be a valid ID in the DB) because as far as I know you don't set IDs for new entities on the client. This all would work fine if I was transferring the LINQ to SQL classes via my RIA services, because even though the Album insert includes the Artist and the Artist insert includes the Album, both are Entities and the L2S context recognizes them. However, with my custom presentation model objects, I need to convert them back to the LINQ to SQL classes maintaining the associations in the process so they can be added to the L2S context. Put simply, as far as I can tell, this is impossible. Each entity gets its own Insert call, but there's no way you can just insert the one entity because without IDs the associations are lost. If the database used GUID identifiers it would be a different story because I could set those on the client. Is this possible, or should I be pursuing another design?

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  • Persisting non-entity class that extends an entity (jpa) - example?

    - by Michal Minicki
    The JPA tutorial states that one can have a non-entity that extends entity class: Entities may extend both entity and non-entity classes, and non-entity classes may extend entity classes. - http://java.sun.com/javaee/5/docs/tutorial/doc/bnbqa.html Is it possible to persist such structure? I want to do this: @Entity abstract class Test { ... } class FirstConcreteTest extends Test { ... } // Non-ntity class SecondConcreteTest extends Test { ... } // Non-entity Test test = new FirstConcreteTest(); em.persist(test); What I would like it to do is to persist all fields mapped on abstract Test to a common database table for all concrete classes (first and second), leaving all fields of first and second test class unpersisted (these can contain stuff like EJBs, jdbc pools, etc). And a bonus question. Is it possible to persist abstract property too? @Entity abstract class Test { @Column @Access(AccessType.PROPERTY) abstract public String getName(); } class SecondConcreteTest extends Test { public String getName() { return "Second Concrete Test"; } }

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  • Beginner Question on traversing a EF4 model

    - by user564577
    I have a basic EF4 model with two entities. I'm using Self Tracking Entities Client has ClientAddresses relationship on clientkey = clientkey. (1 to many) How do i get a list/collection of client entities (STE) and their addresses (STE) but only ones where they live in a particular state or some such filter on the address??? This seems to filter and bring back clients but doesnt bring back addresses. var j = from client in context.Clients where client.ClientAddresses.All(c => c.ZIP == "80923") select client; I cant get this to create the Addresses because ClientAddresses is IEnumerable and it needs a TrackableCollection var query = from t1 in context.Clients join t2 in context.ClientAddresses on t1.ClientKey equals t2.ClientKey where t2.ZIP == "80923" select new Client { FirstName = t1.FirstName, LastName = t1.LastName, IsEnabled = t1.IsEnabled, ClientKey = t1.ClientKey, ChangeUser = t1.ChangeUser, ChangeDate = t1.ChangeDate, ClientAddresses = from a in t1.ClientAddresses select new ClientAddress { AddressKey = a.AddressKey, AddressLine1 = a.AddressLine1, AddressLine2 = a.AddressLine2, AddressTypeCode = a.AddressTypeCode, City = a.City, ClientKey = a.ClientKey, State = a.State, ZIP = a.ZIP } }; Any pointers would be appreciated. Thanks Edit: This seems to work.... var j = from client in context.Clients.Include("ClientAddresses") where client.ClientAddresses.Any(c => c.ZIP == "80923") select client;

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  • Visual Studio Talk Show #115 is now online - Entity Framework 4 (French)

    - by guybarrette
    http://www.visualstudiotalkshow.com Matthieu Mezil: Entity Framework 4 Nous discutons avec Matthieu Mezil de la version 4 de Entity Framework (EF4). Entre autres, on évaluera avec Matthieu en quoi cette nouvelle version qui sera inclus avec Visual Studio 2010 permet de concevoir un ORM (Object Relational Mapper) avec une implémentation Agile. Matthieu Mezil est consultant formateur chez Access IT à Paris. MVP C# et speaker INETA, il s’est spécialisé sur l’Entity Framework. Il anime régulièrement des conférences sur ce sujet, notamment dans le cadre d’évènements Microsoft. MCT, Matthieu a également écrit plusieurs formations sur la POO, le langage C# et bien sûr sur l’Entity Framework qu’il anime fréquemment. Dans le cadre de son travail, il est souvent amené à travailler avec le Microsoft Technology Center de Paris. Matthieu est également un bloggeur important: en français sur http://blogs.codes-sources.com/matthieu et en anglais sur http://msmvps.com/blogs/matthieu. Télécharger l'émission Si vous désirez un accès direct au fichier audio en format MP3, nous vous invitons à télécharger le fichier en utilisant un des boutons ci-dessous. Si vous désirez utiliser le feed RSS pour télécharger l'émission, nous vous invitons à vous abonnez en utilisant le bouton ci-dessous. Si vous désirez utiliser le répertoire iTunes Podcast pour télécharger l'émission, nous vous encourageons à vous abonnez en utilisant le bouton ci-dessous. var addthis_pub="guybarrette";

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  • How do I update with a newly-created detached entity using NHibernate?

    - by Daniel T.
    Explanation: Let's say I have an object graph that's nested several levels deep and each entity has a bi-directional relationship with each other. A -> B -> C -> D -> E Or in other words, A has a collection of B and B has a reference back to A, and B has a collection of C and C has a reference back to B, etc... Now let's say I want to edit some data for an instance ofC. In Winforms, I would use something like this: var instanceOfC; using (var session = SessionFactory.OpenSession()) { // get the instance of C with Id = 3 instanceOfC = session.Linq<C>().Where(x => x.Id == 3); } SendToUIAndLetUserUpdateData(instanceOfC); using (var session = SessionFactory.OpenSession()) { // re-attach the detached entity and update it session.Update(instanceOfC); } In plain English, we grab a persistent instance out of the database, detach it, give it to the UI layer for editing, then re-attach it and save it back to the database. Problem: This works fine for Winform applications because we're using the same entity all throughout, the only difference being that it goes from persistent to detached to persistent again. The problem occurs when I'm using a web service and a browser, sending over JSON data. In this case, the data that comes back is no longer a detached entity, but rather a transient one that just happens to have the same ID as the persistent one. If I use this entity to update, it will wipe out the relationship to B and D unless I sent the entire object graph over to the UI and got it back in one piece. Question: My question is, how do I serialize detached entities over the web, receive them back, and save them, while preserving any relationships that I didn't explicitly change? I know about ISession.SaveOrUpdateCopy and ISession.Merge() (they seem to do the same thing?), but this will still wipe out the relationships if I don't explicitly set them. I could copy the fields from the transient entity to the persistent entity one by one, but this doesn't work too well when it comes to relationships and I'd have to handle version comparisons manually.

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  • EF 4’s PluralizationService Class: A Singularly Impossible Plurality

    - by Ken Cox [MVP]
    Entity Framework’s new 4.0 designer does its best to generate correct plural and singular forms of object names. This magic is done through the PluralizationService Class found in the System.Data.Entity.Design.PluralizationServices namespace and in the System.Data.Entity.Design.dll assembly. [Before you ask… Yes, I’ll post my example page, the service, and the project source code as soon as my ISP makes ASP.NET 4 RTM available. Stay tuned.] Anyone who speaks English is brutally aware of the ridiculous...(read more)

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  • Sprite and Physics components or sub-components?

    - by ashes999
    I'm taking my first dive into creating a very simple entity framework. The key concepts (classes) are: Entity (has 0+ components, can return components by type) SpriteEntity (everything you need to draw on screen, including lighting info) PhysicsEntity (velocity, acceleration, collision detection) I started out with physics notions in my sprite component, and then later removed them to a sub-component. The separation of concerns makes sense; a sprite is enough information to draw anything (X, Y, width, height, lighting, etc.) and physics piggybacks (uses the parent sprite to get X/Y/W/H) while adding physics notions of velocity and collisions. The problem is that I would like collisions to be on an entity level -- meaning "no matter what your representation is (be it sprites, text, or something else), collide against this entity." So I refactored and redirected collision handling from entities to sprite.physics, while mapping and returning the right entity on physics collisions. The problem is that writing code like this.GetComponent<SpriteComponent>().physics is a violation of abstraction. Which made me think (this is the TLDR): should I keep physics as a separate component from sprites, or a sub-component, or something else? How should I share data and separate concerns?

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  • Link dos meus melhores artigos

    - by renatohaddad
    Olá pessoal, resolvi agregar os links dos meus melhores artigos.Engenharia Reversa no Entity Framework 5 http://msdn.microsoft.com/pt-br/library/jj856239.aspxDados Geográficos no Entity Framework 5 e SQL Server 2012 http://msdn.microsoft.com/pt-br/library/jj900151.aspxManutenção de Dados no Entity Framework 4 http://msdn.microsoft.com/pt-br/library/jj128160.aspxPOCO no Entity Framework 4 http://msdn.microsoft.com/pt-br/library/ff978717.aspxA importância e o uso do Data Annotation http://msdn.microsoft.com/pt-br/library/jj129537.aspxUso de parâmetros Opcionais no Visual C# 4 http://msdn.microsoft.com/pt-br/library/jj218324.aspxBing Maps no Windows Phone 7.5  http://msdn.microsoft.com/pt-br/library/hh972467.aspxWindows Phone 7 - dados de OData  http://msdn.microsoft.com/pt-br/library/hh972465.aspxReconhecimento de Voz no Windows Phone 8 http://msdn.microsoft.com/pt-br/library/jj856240.aspx Saibam que quase todos estes temas abordados nos artigos eu tenho em detalhes nos treinamentos via download em http://www.renatohaddad.com/loja.Bons estudos e sucesso nos projetos!Renatão

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  • Xna model parts are overlying others

    - by Federico Chiaravalli
    I am trying to import in XNA an .fbx model exported with blender. Here is my drawing code public void Draw() { Matrix[] modelTransforms = new Matrix[Model.Bones.Count]; Model.CopyAbsoluteBoneTransformsTo(modelTransforms); foreach (ModelMesh mesh in Model.Meshes) { foreach (BasicEffect be in mesh.Effects) { be.EnableDefaultLighting(); be.World = modelTransforms[mesh.ParentBone.Index] * GameCamera.World * Translation; be.View = GameCamera.View; be.Projection = GameCamera.Projection; } mesh.Draw(); } } The problem is that when I start the game some model parts are overlying others instead of being behind. I've tried to download other models from internet but they have the same problem.

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  • How a "Collision System" should be implemented?

    - by nathan
    My game is written using a entity system approach using Artemis Framework. Right know my collision detection is called from the Movement System but i'm wondering if it's a proper way to do collision detection using such an approach. Right know i'm thinking of a new system dedicated to collision detection that would proceed all the solid entities to check if they are in collision with another one. I'm wondering if it's a correct way to handle collision detection with an entity system approach? Also, how should i implement this collision system? I though of an IntervalEntitySystem that would check every 200ms (this value is chosen regarding the Artemis documentation) if some entities are colliding. protected void processEntities(ImmutableBag<Entity> ib) { for (int i = 0; i < ib.size(); i++) { Entity e = ib.get(i); //check of collision with other entities here } }

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  • How should I implement the repository pattern for complex object models?

    - by Eric Falsken
    Our data model has almost 200 classes that can be separated out into about a dozen functional areas. It would have been nice to use domains, but the separation isn't that clean and we can't change it. We're redesigning our DAL to use Entity Framework and most of the recommendations that I've seen suggest using a Repository pattern. However, none of the samples really deal with complex object models. Some implementations that I've found suggest the use of a repository-per-entity. This seems ridiculous and un-maintainable for large, complex models. Is it really necessary to create a UnitOfWork for each operation, and a Repository for each entity? I could end up with thousands of classes. I know this is unreasonable, but I've found very little guidance implementing Repository, Unit Of Work, and Entity Framework over complex models and realistic business applications.

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  • Organizing your Data Access Layer

    - by nighthawk457
    I am using Entity Framework as my ORM in an ASP.Net application. I have my database already created so ended up generating the entity model from it. What is a good way to organize files/classes in the data access layer. My entity framework model is in a class library and I was planning on adding additional classes per Entity(i.e per database table) and putting all the queries related to those tables in their respective classes. I am not sure if this is a right approach and if it is then where do the queries requiring data from multiple tables go? Am I completely wrong in organizing my files based on entities/tables and should I organize them based on functional areas instead.

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  • DTO or Domain Model Object in the View Layer?

    - by smayers81
    I know this is probably an age-old question, but what is the better practice? Using a domain model object throughout all layers of your application, and even binding values directly to them on the JSP (I'm using JSF). Or convert a domain model object into a DTO in the DAO or Service layer and send a lightweight DTO to the presentation layer. I have been told it makes no sense to use DTOs because changes to the database will result in changes to all your DTOs whereas using Model Objects everywhere will just require changes to the affected model object. However, the ease of use and the lightweight nature of DTOs seems to outweigh that. I should note that my app uses Hibernate Model Objects AND uses its own custom-created model objects (meaning not bound to any DB session, always detached). Is either of the above scenarios more beneficial to a strict Model Object pattern? Using Hibernate has been a huge PITA with regards to things like Lazy Initialization Exceptions.

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  • Entity Framework - in model first, how do I get my EF classes to be based on the existing domain cla

    - by Greg
    Hi, If I already have domain classes, and I want to be able persist them using EF via a model first approach how do I do this? For example do I go to the EF designer (in VS2010) and create the model and generate the classes, then go to these EF classes and somehow manually modify them? But then would there be an issue if I needed to change the model and re-create database TSQL from the model for updates? What's the easiest approach?

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  • changing the saved contents of the model , edit model fileds once saved

    - by imran-glt
    hi I have extended the user model and added extra fields to it i.e "latitude" "longitude" and status and than save it. up to here it works fine. but i want to allow the user to change his/her "latitude" "longitude" whenever he/she needs like the hotmail and yahoo allows change account feature. in my case the user only wants to chage the latitude and longitude i tried it in this way but it didnt work. is this the right way to do it ...... or is there any other way to change the saved contents view.py def status_change(request): print "status_change function called" if request.method == "POST": rform = registerForm(data = request.POST) uform = UserForm(data = request.POST) if rform.is_valid(): user = uform.save() register = rform.save() register.user = user register.save() return render_to_response('home.html') else: rform = registerForm() return render_to_response('status_change.html',{'rform':rform})

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  • How to get the app a Django model is from?

    - by e-satis
    I have a model with a generic relation: TrackedItem --- genericrelation ---> any model I would like to be able to generically get, from the initial model, the tracked item. I should be able to do it on any model without modifying it. To do that I need to get the content type and the object id. Getting the object id is easy since I have the model instance, but getting the content type is not: ContentType.object.filter requires the model (which is just content_object.__class__.__name__) and the app_label. I have no idea of how to get in a reliable way the app in which a model is. For now I do app = content_object.__module__.split(".")[0], but it doesn't work with django contrib apps.

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  • MVVM/Presentation Model With WinForms

    - by Erik Ashepa
    Hi, I'm currently working on a brownfield application, it's written with winforms, as a preparation to use WPF in a later version, out team plans to at least use the MVVM/Presentation model, and bind it against winforms... I've explored the subject, including the posts in this site (which i love very much), when boiled down, the main advantage of wpf are : binding controls to properties in xaml. binding commands to command objects in the viewmodel. the first feature is easy to implement (in code), or with a generic control binder, which binds all the controls in the form. the second feature is a little harder to implement, but if you inherit from all your controls and add a command property (which is triggered by an internal event such as click), which is binded to a command instance in the ViewModel. The challenges I'm currently aware of are : implementing a commandmanager, (which will trigger the CanInvoke method of the commands as necessery. winforms only supports one level of databinding : datasource, datamember, wpf is much more flexible. am i missing any other major features that winforms lacks in comparison with wpf, when attempting to implement this design pattern? i sure many of you will recommend some sort of MVP pattern, but MVVM/Presentation model is the way to go for me, because I'll want future WPF support. Thanks in advance, Erik.

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