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  • Error installing scipy on Mountain Lion with Xcode 4.5.1

    - by Xster
    Environment: Mountain Lion 10.8.2, Xcode 4.5.1 command line tools, Python 2.7.3, virtualenv 1.8.2 and numpy 1.6.2 When installing scipy with pip install -e "git+https://github.com/scipy/scipy#egg=scipy-dev" on a fresh virtualenv. llvm-gcc: scipy/sparse/linalg/eigen/arpack/ARPACK/FWRAPPERS/veclib_cabi_c.c In file included from /System/Library/Frameworks/vecLib.framework/Headers/vecLib.h:43, from /System/Library/Frameworks/Accelerate.framework/Headers/Accelerate.h:20, from scipy/sparse/linalg/eigen/arpack/ARPACK/FWRAPPERS/veclib_cabi_c.c:2: /System/Library/Frameworks/vecLib.framework/Headers/vfp.h:51:23: error: immintrin.h: No such file or directory In file included from /System/Library/Frameworks/vecLib.framework/Headers/vecLib.h:43, from /System/Library/Frameworks/Accelerate.framework/Headers/Accelerate.h:20, from scipy/sparse/linalg/eigen/arpack/ARPACK/FWRAPPERS/veclib_cabi_c.c:2: /System/Library/Frameworks/vecLib.framework/Headers/vfp.h: In function ‘vceilf’: /System/Library/Frameworks/vecLib.framework/Headers/vfp.h:53: error: incompatible types in return /System/Library/Frameworks/vecLib.framework/Headers/vfp.h: In function ‘vfloorf’: /System/Library/Frameworks/vecLib.framework/Headers/vfp.h:54: error: incompatible types in return /System/Library/Frameworks/vecLib.framework/Headers/vfp.h: In function ‘vintf’: /System/Library/Frameworks/vecLib.framework/Headers/vfp.h:55: error: ‘_MM_FROUND_TRUNC’ undeclared (first use in this function) /System/Library/Frameworks/vecLib.framework/Headers/vfp.h:55: error: (Each undeclared identifier is reported only once /System/Library/Frameworks/vecLib.framework/Headers/vfp.h:55: error: for each function it appears in.) /System/Library/Frameworks/vecLib.framework/Headers/vfp.h:55: error: incompatible types in return /System/Library/Frameworks/vecLib.framework/Headers/vfp.h: In function ‘vnintf’: /System/Library/Frameworks/vecLib.framework/Headers/vfp.h:56: error: ‘_MM_FROUND_NINT’ undeclared (first use in this function) /System/Library/Frameworks/vecLib.framework/Headers/vfp.h:56: error: incompatible types in return In file included from /System/Library/Frameworks/vecLib.framework/Headers/vecLib.h:43, from /System/Library/Frameworks/Accelerate.framework/Headers/Accelerate.h:20, from scipy/sparse/linalg/eigen/arpack/ARPACK/FWRAPPERS/veclib_cabi_c.c:2: /System/Library/Frameworks/vecLib.framework/Headers/vfp.h:51:23: error: immintrin.h: No such file or directory In file included from /System/Library/Frameworks/vecLib.framework/Headers/vecLib.h:43, from /System/Library/Frameworks/Accelerate.framework/Headers/Accelerate.h:20, from scipy/sparse/linalg/eigen/arpack/ARPACK/FWRAPPERS/veclib_cabi_c.c:2: /System/Library/Frameworks/vecLib.framework/Headers/vfp.h: In function ‘vceilf’: /System/Library/Frameworks/vecLib.framework/Headers/vfp.h:53: error: incompatible types in return /System/Library/Frameworks/vecLib.framework/Headers/vfp.h: In function ‘vfloorf’: /System/Library/Frameworks/vecLib.framework/Headers/vfp.h:54: error: incompatible types in return /System/Library/Frameworks/vecLib.framework/Headers/vfp.h: In function ‘vintf’: /System/Library/Frameworks/vecLib.framework/Headers/vfp.h:55: error: ‘_MM_FROUND_TRUNC’ undeclared (first use in this function) /System/Library/Frameworks/vecLib.framework/Headers/vfp.h:55: error: (Each undeclared identifier is reported only once /System/Library/Frameworks/vecLib.framework/Headers/vfp.h:55: error: for each function it appears in.) /System/Library/Frameworks/vecLib.framework/Headers/vfp.h:55: error: incompatible types in return /System/Library/Frameworks/vecLib.framework/Headers/vfp.h: In function ‘vnintf’: /System/Library/Frameworks/vecLib.framework/Headers/vfp.h:56: error: ‘_MM_FROUND_NINT’ undeclared (first use in this function) /System/Library/Frameworks/vecLib.framework/Headers/vfp.h:56: error: incompatible types in return error: Command "/usr/bin/llvm-gcc -fno-strict-aliasing -Os -w -pipe -march=core2 -msse4 -fwrapv -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -Iscipy/sparse/linalg/eigen/arpack/ARPACK/SRC -I/Users/xiao/.virtualenv/lib/python2.7/site-packages/numpy/core/include -c scipy/sparse/linalg/eigen/arpack/ARPACK/FWRAPPERS/veclib_cabi_c.c -o build/temp.macosx-10.4-x86_64-2.7/scipy/sparse/linalg/eigen/arpack/ARPACK/FWRAPPERS/veclib_cabi_c.o" failed with exit status 1 Is it supposed to be looking for headers from my system frameworks? Is the development version of scipy no longer good for the latest version of Mountain Lion/Xcode?

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  • Microsoft SQL Server Management Studio not working after installing .Net Framework 4

    - by smith watson
    Yesterday I installed .Net Framework 4 as it was required by Liquid XML Studio, but just after installing it, My SQL Server Management Studio stopped working. As soon as open the IDE I get package microsoft sql management studio package failed to load I tried pretty much all the solution posted on the internet but could not get it working, today when I removed the .Net Framework 4, SQL server management studio started working again. Then just to test, I installed the .Net Framework 4 back ... and I started getting the same problem in management studio. I want both on my machine ! how can i do it ? PS : OS is Windows 7

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  • Trying to reinstalling .net framework 4 on windows server 2003 SP2

    - by LBR
    I had a problem with an application that was using .net framework 4. So I tried to fix the installation but it didn't solved. So I proceed to uninstall the framework and install it again. But then the problems started... the setup just wouldn't finish to download the framework. So i tried the full installer, and then it got stuck (freezes) at "installing client profile"... The server works well but the installation progress bar just stays at the same place (but the "wheel" keeps turning, like it was doing something, but stays like this for hours...) I tried the .net clean unistall software but the problem remains. I'm all out of ideas... I've searched the web but couldn't solve the problem with any solution I found... Any ideas on how to force the installation?

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  • Implementing my Entity System. Questions about some problems I have found.

    - by Notbad
    Hi!, Well during this week I have deciding about implementation of my entity system. It is a big topic so it has been difficult to take one option from the whole. This has been my decision: 1) I don't have an entity class it is just an id. 2) I have systems that contain a list of components (the list is homegenous, I mean, RenderSystem will just have RenderComponents). 3) Compones will be just data. 4) There would be some kind of "entity prototypes" in a manager or something from we will create entity instances.Ideally they will define the type of components it has and initialization data. 5) Prototype code to create an entity (this is from the top of my head): int id=World::getInstance()->createEntity("entity template"); 6) This will notify all systems that a new entity has been created, and if the entity needs a component that the system handles it will add it to the entity. Ok, this are the ideas. Let's see if some can help with the problems: 1) The main problem is this templates that are sent to the systems in creation process to populate the entity with needed components. What would you use, an OR(ed) int?, a list of strings?. 2) How to do initialization for components when the entity has been created? How to store this in the template? I have thought about having a function in the template that is virtual and after entity is created an populated, gets the components and sets initialization values. 3) Don't you think this is a lot of work for just an entity creation?. Sorry for the long post, I have tried to expose my ideas and finding in order other could have a start beside exposing my problems. Thanks in advance, Notbad.

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  • Using FluentValidation with Castle Windsor and Entity Framework 4.0 (POCO) in MVC2

    - by Brian McCord
    This isn't a very simple question, but hopefully someone has run across it. I am trying to get the following things working together: MVC2 FluentValidation Entity Framework 4.0 (POCO) Castle Windsor I've pretty much gotten everything working. I have Castle Windsor implemented and working with the Controllers being served up by the WindsorControllerFactory that is part of MVCContrib. I also have Castle serving up the FluentValidation validators as is described by this article: http://www.jeremyskinner.co.uk/2010/02/22/using-fluentvalidation-with-an-ioc-container/ My problem comes in when I try to use Html.EditorForModel or EditorFor on a view. When I try to do that I get this error message: No component for supporting the service FluentValidation.IValidator`1[[System.Data.Entity.DynamicProxies.State_71C51A42554BA6C3CF05105DA05435AD209602C217FC4C34CA52ACEA2B06B99B, EntityFrameworkDynamicProxies-BrindleyInsurance.BusinessObjects, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]] was found This is due to using the POCO generation on Entity Framework 4.0. At runtime, the generated classes get wrapped with a Dynamic Proxy so tracking and lazy loading can happen. Apparently, when using EditorForModel or EditorFor, it tries to ask Windsor to create a validator for the dynamic proxy type instead of the underlying real type. Does anyone know what I can do to solve this issue?

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  • Using Entity Framework with an SQL Compact Private Installation

    - by David Veeneman
    I am using Entity Framework 4 in a desktop application with SQL Compact. I want to use a private installation of SQL Compact with my application, so that my installer can install SQL Compact without giving the user a second installation to do. It also avoids versioning hassles down the road. My development machine has SQL Compact 3.5 SP1 installed as a public installation, so my app runs fine there, as one would expect. But it's not running on my test machine, which does not have SQL Compact installed. I get this error: The specified store provider cannot be found in the configuration, or is not valid. I know some people have had difficulty with SQL Compact private installations, but I have used them for a while, and I really like them. Unfortunately, my regular private installation approach isn't working. I have checked the version numbers on my SQL CE files, and they are all 3.8.8078.0, which is the SP2 RC version. Here are the files I have included in my private installation: sqlcecompact35.dll sqlceer35EN.dll sqlceme35.dll sqlceqp35.dll sqlcese35.dll System.Data.SqlServerCe.dll System.Data.SqlServerCe.Entity.dll I have added a reference to System.Data.SqlServerCe to my project, and I have verified that all of the files listed above are being copied to the application folder on the installation machine. Here is the code I use to configure an EntityConnectionStringBuilder when I open a SQL Compact file: var sqlCompactConnectionString = string.Format("Data Source={0}", filePath); // Set Builder properties builder.Metadata = string.Format("res://*/{0}.csdl|res://*/{0}.ssdl|res://*/{0}.msl", edmName); builder.Provider = "System.Data.SqlServerCe.3.5"; builder.ProviderConnectionString = sqlCompactConnectionString; var edmConnectionString = builder.ToString(); Am I missing a file? Am I missing a configuration stepp needed to tell Entity Framework where to find my SQL Compact DLLs? Any other suggestions why EF isn't finding my SQL Compact DLLs on the installation machine? Thanks for your help.

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  • Update a single field from a single entity with ria-services

    - by TimothyP
    There are situations where I only want to update a specific field of a single entity in the database. I loaded the entities of that type into my silverlight application, and I know they are constantly changing on the server... but there is one field which has to be set by the silverlight client... the server will only read it. How can I just send the new data for that field to the server? Example an Entity called "TextField". I have a list of TextFields loaded in the silverlight application and every now and then the user will update the Preload (string) property of an entity and that has to go back to the server without changing anything else on the server. I tried adding a simple SetPreloadText(...) method to the DomainService but that just makes Silverlight crash with some odd error code. Is there a way to this? Am I working against the idea of Silverlight here? I really don't want to send the entire object back because know that at any given time the version on the client will most likely be out of date. (which is ok for this specific application)

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  • One Model to Rule Them All - VS2010 UML, ADO.NET Entity Data Model, and T4

    - by Eric J.
    I worked on a fairly large project a while back where we modeled the classes in Enterprise Architect and generated the (partial) POCO classes (complete with model-driven business rule validations), persistence (NHibernate mapping file) and DDL. Based on certain model attributes we could flag alternate generation strategies or indicate that a particular portion would be entirely hand-coded. There was a good deal of initial investment, but it paid large dividends over the lifetime of a 15 developer, 3 year project. I'm investigating doing something similar with the current Microsoft technology stack. The place I'm stuck is that class modeling is done with the VS 2010 UML tools, but logical data modeling is done with Entity Data Modeler. Is it a reasonable path to use VS 2010 UML as the "single source of truth" and code generate the edmx files based on the class model? That's the inverse of the common path to create the entity model and use a POCO generator to generate classes. However, a good class model can be used to generate much more than just the properties so I tend to view it as a better choice than the entity model.

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  • Entity Framework with ASP.NET MVC. Updating entity problem

    - by Kitaly
    Hi people. I'm trying to update an entity and its related entities as well. For instance, I have a class Car with a property Category and I want to change its Category. So, I have the following methods in the Controller: public ActionResult Edit(int id) { var categories = context.Categories.ToList(); ViewData["categories"] = new SelectList(categories, "Id", "Name"); var car = context.Cars.Where(c => c.Id == id).First(); return PartialView("Form", car); } [AcceptVerbs(HttpVerbs.Post)] public ActionResult Edit(Car car) { var category = context.Categories.Where(c => c.Id == car.Category.Id).First(); car.Category = category; context.UpdateCar(car); context.SaveChanges(); return RedirectToAction("Index"); } The UpdateCar method, in ObjectContext class, follows: public void UpdateCar(Car car) { var attachedCar = Cars.Where(c => c.Id == car.Id).First(); ApplyItemUpdates(attachedCar, car); } private void ApplyItemUpdates(EntityObject originalItem, EntityObject updatedItem) { try { ApplyPropertyChanges(originalItem.EntityKey.EntitySetName, updatedItem); ApplyReferencePropertyChanges(updatedItem, originalItem); } catch (InvalidOperationException ex) { Console.WriteLine(ex.ToString()); } } public void ApplyReferencePropertyChanges(IEntityWithRelationships newEntity, IEntityWithRelationships oldEntity) { foreach (var relatedEnd in oldEntity.RelationshipManager.GetAllRelatedEnds()) { var oldRef = relatedEnd as EntityReference; if (oldRef != null) { var newRef = newEntity.RelationshipManager.GetRelatedEnd(oldRef.RelationshipName, oldRef.TargetRoleName) as EntityReference; oldRef.EntityKey = newRef.EntityKey; } } } The problem is that when I set the Category property after the POST in my controller, the entity state changes to Added instead of remaining as Detached. How can I update one-to-one relationship with Entity Framework and ASP.NET MVC without setting all the properties, one by one like this post?

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  • Converting a Linq expression tree that relies on SqlMethods.Like() for use with the Entity Framework

    - by JohnnyO
    I recently switched from using Linq to Sql to the Entity Framework. One of the things that I've been really struggling with is getting a general purpose IQueryable extension method that was built for Linq to Sql to work with the Entity Framework. This extension method has a dependency on the Like() method of SqlMethods, which is Linq to Sql specific. What I really like about this extension method is that it allows me to dynamically construct a Sql Like statement on any object at runtime, by simply passing in a property name (as string) and a query clause (also as string). Such an extension method is very convenient for using grids like flexigrid or jqgrid. Here is the Linq to Sql version (taken from this tutorial: http://www.codeproject.com/KB/aspnet/MVCFlexigrid.aspx): public static IQueryable<T> Like<T>(this IQueryable<T> source, string propertyName, string keyword) { var type = typeof(T); var property = type.GetProperty(propertyName); var parameter = Expression.Parameter(type, "p"); var propertyAccess = Expression.MakeMemberAccess(parameter, property); var constant = Expression.Constant("%" + keyword + "%"); var like = typeof(SqlMethods).GetMethod("Like", new Type[] { typeof(string), typeof(string) }); MethodCallExpression methodExp = Expression.Call(null, like, propertyAccess, constant); Expression<Func<T, bool>> lambda = Expression.Lambda<Func<T, bool>>(methodExp, parameter); return source.Where(lambda); } With this extension method, I can simply do the following: someList.Like("FirstName", "mike"); or anotherList.Like("ProductName", "widget"); Is there an equivalent way to do this with Entity Framework? Thanks in advance.

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  • Entity Framework: Auto-updating foreign key when setting a new object reference

    - by Adrian Grigore
    Hi, I am porting an existing application from Linq to SQL to Entity Framework 4 (default code generation). One difference I noticed between the two is that a foreign key property are not updated when resetting the object reference. Now I need to decide how to deal with this. For example supposing you have two entity types, Company and Employee. One Company has many Employees. In Linq To SQL, setting the company also sets the company id: var company=new Company(ID=1); var employee=new Employee(); Debug.Assert(employee.CompanyID==0); employee.Company=company; Debug.Assert(employee.CompanyID==1); //Works fine! In Entity Framework (and without using any code template customization) this does not work: var company=new Company(ID=1); var employee=new Employee(); Debug.Assert(employee.CompanyID==0); employee.Company=company; Debug.Assert(employee.CompanyID==1); //Throws, since CompanyID was not updated! How can I make EF behave the same way as LinqToSQL? I had a look at the default code generation T4 template, but I could not figure out how to make the necessary changes.

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  • Entity Framework and associations between string keys

    - by fredrik
    Hi, I am new to Entity Framework, and ORM's for that mather. In the project that I'm involed in we have a legacy database, with all its keys as strings, case-insensitive. We are converting to MSSQL and want to use EF as ORM, but have run in to a problem. Here is an example that illustrates our problem: TableA has a primary string key, TableB has a reference to this primary key. In LINQ we write something like: var result = from t in context.TableB select t.TableA; foreach( var r in result ) Console.WriteLine( r.someFieldInTableA ); if TableA contains a primary key that reads "A", and TableB contains two rows that references TableA but with different cases in the referenceing field, "a" and "A". In our project we want both of the rows to endup in the result, but only the one with the matching case will end up there. Using the SQL Profiler, I have noticed that both of the rows are selected. Is there a way to tell Entity Framework that the keys are case insensitive? Edit:We have now tested this with NHibernate and come to the conclution that NHibernate works with case-insensitive keys. So NHibernate might be a better choice for us.I am however still interested in finding out if there is any way to change the behaviour of Entity Framework.

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  • entity framework insert bug

    - by tmfkmoney
    I found a previous question which seemed related but there's no resolution and it's 5 months old so I've opened my own version. http://stackoverflow.com/questions/1545583/entity-framework-inserting-new-entity-via-objectcontext-does-not-use-existing-e When I insert records into my database with the following it works fine for a while and then eventually it starts inserting null values in the referenced field. This typically happens after I do an update on my model from the database although not always after I do an update. I'm using a MySQL database for this. I have debugged the code and the values are being set properly before the save event. They're just not getting inserted properly. I can always fix this issue by re-creating the model without touching any of my code. I have to recreate the entire model, though. I can't just dump the relevant tables and re-add them. This makes me think it doesn't have anything to do with my code but something with the entity framework. Does anyone else have this problem and/or solved it? using (var db = new MyModel()) { var stocks = from record in query let ticker = record.Ticker select new { company = db.Companies.FirstOrDefault(c => c.ticker == ticker), price = Convert.ToDecimal(record.Price), date_stamp = Convert.ToDateTime(record.DateTime) }; foreach (var stock in stocks) { if (stock.company != null) { var price = new StockPrice { Company = stock.company, price = stock.price, date_stamp = stock.date_stamp }; db.AddToStockPrices(price); } } db.SaveChanges(); }

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  • Return value mapping on Stored Procedures in Entity Framework

    - by Yucel
    Hi, I am calling a stored procedure with EntityFramework. But custom property that i set in partial entity class is null. I have Entities in my edmx (I called edmx i dont know what to call for this). For example I have a "User" table in my database and so i have a "User" class on my Entity. I have a stored procedure called GetUserById(@userId) and in this stored procedure i am writing a basic sql statement like below "SELECT * FROM Users WHERE Id=@userId" in my edmx i make a function import to call this stored procedure and set its return value to Entities (also select User from dropdownlist). It works perfectly when i call my stored procedure like below User user = Context.SP_GetUserById(123456); But i add a custom new column to stored procedure to return one more column like below SELECT *, dbo.ConcatRoles(U.Id) AS RolesAsString FROM membership.[User] U WHERE Id = @id Now when i execute it from SSMS new column called RolesAsString appear in result. To work this on entity framework i added a new property called RolesAsString to my User class like below. public partial class User { public string RolesAsString{ get; set; } } But this field isnt filled by stored procedure when i call it. I look to the Mapping Detail windows of my SP_GetUserById there isnt a mapping on this window. I want to add but window is read only i cant map it. I looked to the source of edmx cant find anything about mapping of SP. How can i map this custom field?

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  • Saving a single entity instead of the entire context - revisited

    - by nite
    I’m looking for a way to have fine grained control over what is saved using Entity Framework, rather than the whole ObjectContext.SaveChanges(). My scenario is pretty straight forward, and I’m quite amazed not catered for in EF – pretty basic in NHibernate and all other data access paradigms I’ve seen. I’m generating a bunch of data (in a WPF UI) and allowing the user to fine tune what is proposed and choose what is actually committed to the database. For the proposed entities I’m: getting a bunch of reference entities (eg languages) via my objectcontext, creating the proposed entities and assigning these reference entities to them (as navigation properties), so by virtue of their relationship to the reference entities they’re implicitly added to the objectconext Trying to create & save individual entites based on the proposed entities. I figure this should be really simple & trivial but everything I’ve tried I’ve hit a brick wall, either I set up another objectcontext & add just the entity I need (it then tries to add the whole graph and fails as it’s on another objectcontext). I’ve tried MergeOptions = NoTracking on my reference entities to try to get the Attach/AddObject not to navigate through these to create a graph, no avail. I've removed the navigation properties from the reference entities. I've tried AcceptAllChanges, that works but pretty useless in practice as I do still want to track & save other entities. In a simple test, I can create 2 of my proposed entities, AddObject the one I want to save and then Detach the one I dont then call SaveChanges, this works but again not great in practice. Following are a few links to some of the nifty ideas which in the end don’t help in the end but illustrate the complexity of EF for something so simple. I’m really looking for a SaveSingle/SaveAtomic method, and think it’s a pretty reasonable & basic ask for any DAL, letalone a cutting edge ORM. http://stackoverflow.com/questions/1301460/saving-a-single-entity-instead-of-the-entire-context www.codeproject.com/KB/architecture/attachobjectgraph.aspx?fid=1534536&df=90&mpp=25&noise=3&sort=Position&view=Quick&select=3071122&fr=1 bernhardelbl.spaces.live.com/blog/cns!DB54AE2C5D84DB78!238.entry

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  • Entity Framework Validation & usage

    - by kmsellers
    I'm aware there is an AssociationChanged event, however, this event fires after the association is made. There is no AssociationChanging event. So, if I want to throw an exception for some validation reason, how do I do this and get back to my original value? Also, I would like to default values for my entity based on information from other entities but do this only when I know the entitiy is instanced for insertion into the database. How do I tell the difference between that and the object getting instanced because it is about to be populated based on existing data? Am I supposed to know? Is that considiered business logic that should be outside of my entity business logic? If that's the case, then should I be designing controller classes to wrap all these entities? My concern is that if I deliver back an entity, I want the client to get access to the properties, but I want to retain tight control over validations on how they are set, defaulted, etc. Every example I've seen references context, which is outside of my enity partial class validation, right? BTW, I looked at the EFPocoAdapter and for the life of me cannot determine how to populate lists of from within my POCO class... anyone know how I get to the context from a EFPoco Class?

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  • Stopping Filter Display in Dynamic Data Entity Web App

    - by bert
    I'm currently experimenting with the Dynamic Data Entity Web App Project type in VS2008 SP1 and after reading many tutorials which offer helpful advice for problems I so far have no need of a solution to I have fallen at the first hurdle. In the DB I have made my entity model from I decided to start small with a table called "Companies" just to see if I could tweak the display into a satisfactory shape for this small table. The Companies table has a column called "contactid" which leads to a record filled with various contact information in a "contacts" table. The default created Entity Data Model has guessed that One companies could have many contact records. So it tries to be helpful and add a "Contact" filter onto the page that allows you to see all the Companies that share a particular set of contact info indexed by the "Contact Name" field. Unfortunately the contact table is a multi-purpose one that also stores contact info for customers and there are about 1000 times more customers than there are companies. So the Dropdown makes the page load time increase exponentially and produces no benefit. So I'd like to just stop the filter from appearing. Only problem is I don't have a clue how to switch it off. Google is so far proving recalcitrant on the matter so I wondered if anyone in here knew how to get rid of a useless filter.

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  • UpdateModelFromDatabaseException when trying to add a table to Entity Framework model

    - by Agent_9191
    I'm running into a weird issue with Entity Framework in .NET 3.5 SP1 within Visual Studio 2008. I created a database with a few tables in SQL Server and then created the associated .edmx Entity Framework model and had no issues. I then created a new table in the database that has a foreign key to an existing table and needed to be added to the .edmx. So I opened the .edmx in Visual Studio and in the models right-clicked and chose "Update Model From Database...". I saw the new table in the "add" tab, so I checked it and clicked finish. However I get an error message with the following text: --------------------------- Microsoft Visual Studio --------------------------- An exception of type 'Microsoft.Data.Entity.Design.Model.Commands.UpdateModelFromDatabaseException' occurred while attempting to update from the database. The exception message is: 'Cannot update from the database. Cannot resolve the Name Target for ScalarProperty 'ID <==> CustomerID'.'. --------------------------- OK --------------------------- For reference, here's the tables seem to be the most pertinent to the error. CustomerPreferences already exists in the .edmx. Diets is the table that was added afterwards and trying to add to the .edmx. CREATE TABLE [dbo].[CustomerPreferences]( [ID] [uniqueidentifier] NOT NULL, [LastUpdatedTime] [datetime] NOT NULL, [LastUpdatedBy] [uniqueidentifier] NOT NULL, PRIMARY KEY CLUSTERED ( [ID] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] CREATE TABLE [dbo].[Diets]( [ID] [uniqueidentifier] NOT NULL, [CustomerID] [uniqueidentifier] NOT NULL, [Description] [nvarchar](50) NOT NULL, [LastUpdatedTime] [datetime] NOT NULL, [LastUpdatedBy] [uniqueidentifier] NOT NULL, PRIMARY KEY CLUSTERED ( [ID] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] GO ALTER TABLE [dbo].[Diets] WITH CHECK ADD CONSTRAINT [FK_Diets_CustomerPreferences] FOREIGN KEY([CustomerID]) REFERENCES [dbo].[CustomerPreferences] ([ID]) GO ALTER TABLE [dbo].[Diets] CHECK CONSTRAINT [FK_Diets_CustomerPreferences] GO This seems like a fairly common use case, so I'm not sure where I'm going wrong.

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  • What are good design practices when working with Entity Framework

    - by AD
    This will apply mostly for an asp.net application where the data is not accessed via soa. Meaning that you get access to the objects loaded from the framework, not Transfer Objects, although some recommendation still apply. This is a community post, so please add to it as you see fit. Applies to: Entity Framework 1.0 shipped with Visual Studio 2008 sp1. Why pick EF in the first place? Considering it is a young technology with plenty of problems (see below), it may be a hard sell to get on the EF bandwagon for your project. However, it is the technology Microsoft is pushing (at the expense of Linq2Sql, which is a subset of EF). In addition, you may not be satisfied with NHibernate or other solutions out there. Whatever the reasons, there are people out there (including me) working with EF and life is not bad.make you think. EF and inheritance The first big subject is inheritance. EF does support mapping for inherited classes that are persisted in 2 ways: table per class and table the hierarchy. The modeling is easy and there are no programming issues with that part. (The following applies to table per class model as I don't have experience with table per hierarchy, which is, anyway, limited.) The real problem comes when you are trying to run queries that include one or many objects that are part of an inheritance tree: the generated sql is incredibly awful, takes a long time to get parsed by the EF and takes a long time to execute as well. This is a real show stopper. Enough that EF should probably not be used with inheritance or as little as possible. Here is an example of how bad it was. My EF model had ~30 classes, ~10 of which were part of an inheritance tree. On running a query to get one item from the Base class, something as simple as Base.Get(id), the generated SQL was over 50,000 characters. Then when you are trying to return some Associations, it degenerates even more, going as far as throwing SQL exceptions about not being able to query more than 256 tables at once. Ok, this is bad, EF concept is to allow you to create your object structure without (or with as little as possible) consideration on the actual database implementation of your table. It completely fails at this. So, recommendations? Avoid inheritance if you can, the performance will be so much better. Use it sparingly where you have to. In my opinion, this makes EF a glorified sql-generation tool for querying, but there are still advantages to using it. And ways to implement mechanism that are similar to inheritance. Bypassing inheritance with Interfaces First thing to know with trying to get some kind of inheritance going with EF is that you cannot assign a non-EF-modeled class a base class. Don't even try it, it will get overwritten by the modeler. So what to do? You can use interfaces to enforce that classes implement some functionality. For example here is a IEntity interface that allow you to define Associations between EF entities where you don't know at design time what the type of the entity would be. public enum EntityTypes{ Unknown = -1, Dog = 0, Cat } public interface IEntity { int EntityID { get; } string Name { get; } Type EntityType { get; } } public partial class Dog : IEntity { // implement EntityID and Name which could actually be fields // from your EF model Type EntityType{ get{ return EntityTypes.Dog; } } } Using this IEntity, you can then work with undefined associations in other classes // lets take a class that you defined in your model. // that class has a mapping to the columns: PetID, PetType public partial class Person { public IEntity GetPet() { return IEntityController.Get(PetID,PetType); } } which makes use of some extension functions: public class IEntityController { static public IEntity Get(int id, EntityTypes type) { switch (type) { case EntityTypes.Dog: return Dog.Get(id); case EntityTypes.Cat: return Cat.Get(id); default: throw new Exception("Invalid EntityType"); } } } Not as neat as having plain inheritance, particularly considering you have to store the PetType in an extra database field, but considering the performance gains, I would not look back. It also cannot model one-to-many, many-to-many relationship, but with creative uses of 'Union' it could be made to work. Finally, it creates the side effet of loading data in a property/function of the object, which you need to be careful about. Using a clear naming convention like GetXYZ() helps in that regards. Compiled Queries Entity Framework performance is not as good as direct database access with ADO (obviously) or Linq2SQL. There are ways to improve it however, one of which is compiling your queries. The performance of a compiled query is similar to Linq2Sql. What is a compiled query? It is simply a query for which you tell the framework to keep the parsed tree in memory so it doesn't need to be regenerated the next time you run it. So the next run, you will save the time it takes to parse the tree. Do not discount that as it is a very costly operation that gets even worse with more complex queries. There are 2 ways to compile a query: creating an ObjectQuery with EntitySQL and using CompiledQuery.Compile() function. (Note that by using an EntityDataSource in your page, you will in fact be using ObjectQuery with EntitySQL, so that gets compiled and cached). An aside here in case you don't know what EntitySQL is. It is a string-based way of writing queries against the EF. Here is an example: "select value dog from Entities.DogSet as dog where dog.ID = @ID". The syntax is pretty similar to SQL syntax. You can also do pretty complex object manipulation, which is well explained [here][1]. Ok, so here is how to do it using ObjectQuery< string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); The first time you run this query, the framework will generate the expression tree and keep it in memory. So the next time it gets executed, you will save on that costly step. In that example EnablePlanCaching = true, which is unnecessary since that is the default option. The other way to compile a query for later use is the CompiledQuery.Compile method. This uses a delegate: static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => ctx.DogSet.FirstOrDefault(it => it.ID == id)); or using linq static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => (from dog in ctx.DogSet where dog.ID == id select dog).FirstOrDefault()); to call the query: query_GetDog.Invoke( YourContext, id ); The advantage of CompiledQuery is that the syntax of your query is checked at compile time, where as EntitySQL is not. However, there are other consideration... Includes Lets say you want to have the data for the dog owner to be returned by the query to avoid making 2 calls to the database. Easy to do, right? EntitySQL string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)).Include("Owner"); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); CompiledQuery static readonly Func<Entities, int, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, Dog>((ctx, id) => (from dog in ctx.DogSet.Include("Owner") where dog.ID == id select dog).FirstOrDefault()); Now, what if you want to have the Include parametrized? What I mean is that you want to have a single Get() function that is called from different pages that care about different relationships for the dog. One cares about the Owner, another about his FavoriteFood, another about his FavotireToy and so on. Basicly, you want to tell the query which associations to load. It is easy to do with EntitySQL public Dog Get(int id, string include) { string query = "select value dog " + "from Entities.DogSet as dog " + "where dog.ID = @ID"; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>(query, EntityContext.Instance)) .IncludeMany(include); oQuery.Parameters.Add(new ObjectParameter("ID", id)); oQuery.EnablePlanCaching = true; return oQuery.FirstOrDefault(); } The include simply uses the passed string. Easy enough. Note that it is possible to improve on the Include(string) function (that accepts only a single path) with an IncludeMany(string) that will let you pass a string of comma-separated associations to load. Look further in the extension section for this function. If we try to do it with CompiledQuery however, we run into numerous problems: The obvious static readonly Func<Entities, int, string, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, string, Dog>((ctx, id, include) => (from dog in ctx.DogSet.Include(include) where dog.ID == id select dog).FirstOrDefault()); will choke when called with: query_GetDog.Invoke( YourContext, id, "Owner,FavoriteFood" ); Because, as mentionned above, Include() only wants to see a single path in the string and here we are giving it 2: "Owner" and "FavoriteFood" (which is not to be confused with "Owner.FavoriteFood"!). Then, let's use IncludeMany(), which is an extension function static readonly Func<Entities, int, string, Dog> query_GetDog = CompiledQuery.Compile<Entities, int, string, Dog>((ctx, id, include) => (from dog in ctx.DogSet.IncludeMany(include) where dog.ID == id select dog).FirstOrDefault()); Wrong again, this time it is because the EF cannot parse IncludeMany because it is not part of the functions that is recognizes: it is an extension. Ok, so you want to pass an arbitrary number of paths to your function and Includes() only takes a single one. What to do? You could decide that you will never ever need more than, say 20 Includes, and pass each separated strings in a struct to CompiledQuery. But now the query looks like this: from dog in ctx.DogSet.Include(include1).Include(include2).Include(include3) .Include(include4).Include(include5).Include(include6) .[...].Include(include19).Include(include20) where dog.ID == id select dog which is awful as well. Ok, then, but wait a minute. Can't we return an ObjectQuery< with CompiledQuery? Then set the includes on that? Well, that what I would have thought so as well: static readonly Func<Entities, int, ObjectQuery<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, ObjectQuery<Dog>>((ctx, id) => (ObjectQuery<Dog>)(from dog in ctx.DogSet where dog.ID == id select dog)); public Dog GetDog( int id, string include ) { ObjectQuery<Dog> oQuery = query_GetDog(id); oQuery = oQuery.IncludeMany(include); return oQuery.FirstOrDefault; } That should have worked, except that when you call IncludeMany (or Include, Where, OrderBy...) you invalidate the cached compiled query because it is an entirely new one now! So, the expression tree needs to be reparsed and you get that performance hit again. So what is the solution? You simply cannot use CompiledQueries with parametrized Includes. Use EntitySQL instead. This doesn't mean that there aren't uses for CompiledQueries. It is great for localized queries that will always be called in the same context. Ideally CompiledQuery should always be used because the syntax is checked at compile time, but due to limitation, that's not possible. An example of use would be: you may want to have a page that queries which two dogs have the same favorite food, which is a bit narrow for a BusinessLayer function, so you put it in your page and know exactly what type of includes are required. Passing more than 3 parameters to a CompiledQuery Func is limited to 5 parameters, of which the last one is the return type and the first one is your Entities object from the model. So that leaves you with 3 parameters. A pitance, but it can be improved on very easily. public struct MyParams { public string param1; public int param2; public DateTime param3; } static readonly Func<Entities, MyParams, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, MyParams, IEnumerable<Dog>>((ctx, myParams) => from dog in ctx.DogSet where dog.Age == myParams.param2 && dog.Name == myParams.param1 and dog.BirthDate > myParams.param3 select dog); public List<Dog> GetSomeDogs( int age, string Name, DateTime birthDate ) { MyParams myParams = new MyParams(); myParams.param1 = name; myParams.param2 = age; myParams.param3 = birthDate; return query_GetDog(YourContext,myParams).ToList(); } Return Types (this does not apply to EntitySQL queries as they aren't compiled at the same time during execution as the CompiledQuery method) Working with Linq, you usually don't force the execution of the query until the very last moment, in case some other functions downstream wants to change the query in some way: static readonly Func<Entities, int, string, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, IEnumerable<Dog>>((ctx, age, name) => from dog in ctx.DogSet where dog.Age == age && dog.Name == name select dog); public IEnumerable<Dog> GetSomeDogs( int age, string name ) { return query_GetDog(YourContext,age,name); } public void DataBindStuff() { IEnumerable<Dog> dogs = GetSomeDogs(4,"Bud"); // but I want the dogs ordered by BirthDate gridView.DataSource = dogs.OrderBy( it => it.BirthDate ); } What is going to happen here? By still playing with the original ObjectQuery (that is the actual return type of the Linq statement, which implements IEnumerable), it will invalidate the compiled query and be force to re-parse. So, the rule of thumb is to return a List< of objects instead. static readonly Func<Entities, int, string, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, int, string, IEnumerable<Dog>>((ctx, age, name) => from dog in ctx.DogSet where dog.Age == age && dog.Name == name select dog); public List<Dog> GetSomeDogs( int age, string name ) { return query_GetDog(YourContext,age,name).ToList(); //<== change here } public void DataBindStuff() { List<Dog> dogs = GetSomeDogs(4,"Bud"); // but I want the dogs ordered by BirthDate gridView.DataSource = dogs.OrderBy( it => it.BirthDate ); } When you call ToList(), the query gets executed as per the compiled query and then, later, the OrderBy is executed against the objects in memory. It may be a little bit slower, but I'm not even sure. One sure thing is that you have no worries about mis-handling the ObjectQuery and invalidating the compiled query plan. Once again, that is not a blanket statement. ToList() is a defensive programming trick, but if you have a valid reason not to use ToList(), go ahead. There are many cases in which you would want to refine the query before executing it. Performance What is the performance impact of compiling a query? It can actually be fairly large. A rule of thumb is that compiling and caching the query for reuse takes at least double the time of simply executing it without caching. For complex queries (read inherirante), I have seen upwards to 10 seconds. So, the first time a pre-compiled query gets called, you get a performance hit. After that first hit, performance is noticeably better than the same non-pre-compiled query. Practically the same as Linq2Sql When you load a page with pre-compiled queries the first time you will get a hit. It will load in maybe 5-15 seconds (obviously more than one pre-compiled queries will end up being called), while subsequent loads will take less than 300ms. Dramatic difference, and it is up to you to decide if it is ok for your first user to take a hit or you want a script to call your pages to force a compilation of the queries. Can this query be cached? { Dog dog = from dog in YourContext.DogSet where dog.ID == id select dog; } No, ad-hoc Linq queries are not cached and you will incur the cost of generating the tree every single time you call it. Parametrized Queries Most search capabilities involve heavily parametrized queries. There are even libraries available that will let you build a parametrized query out of lamba expressions. The problem is that you cannot use pre-compiled queries with those. One way around that is to map out all the possible criteria in the query and flag which one you want to use: public struct MyParams { public string name; public bool checkName; public int age; public bool checkAge; } static readonly Func<Entities, MyParams, IEnumerable<Dog>> query_GetDog = CompiledQuery.Compile<Entities, MyParams, IEnumerable<Dog>>((ctx, myParams) => from dog in ctx.DogSet where (myParams.checkAge == true && dog.Age == myParams.age) && (myParams.checkName == true && dog.Name == myParams.name ) select dog); protected List<Dog> GetSomeDogs() { MyParams myParams = new MyParams(); myParams.name = "Bud"; myParams.checkName = true; myParams.age = 0; myParams.checkAge = false; return query_GetDog(YourContext,myParams).ToList(); } The advantage here is that you get all the benifits of a pre-compiled quert. The disadvantages are that you most likely will end up with a where clause that is pretty difficult to maintain, that you will incur a bigger penalty for pre-compiling the query and that each query you run is not as efficient as it could be (particularly with joins thrown in). Another way is to build an EntitySQL query piece by piece, like we all did with SQL. protected List<Dod> GetSomeDogs( string name, int age) { string query = "select value dog from Entities.DogSet where 1 = 1 "; if( !String.IsNullOrEmpty(name) ) query = query + " and dog.Name == @Name "; if( age > 0 ) query = query + " and dog.Age == @Age "; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>( query, YourContext ); if( !String.IsNullOrEmpty(name) ) oQuery.Parameters.Add( new ObjectParameter( "Name", name ) ); if( age > 0 ) oQuery.Parameters.Add( new ObjectParameter( "Age", age ) ); return oQuery.ToList(); } Here the problems are: - there is no syntax checking during compilation - each different combination of parameters generate a different query which will need to be pre-compiled when it is first run. In this case, there are only 4 different possible queries (no params, age-only, name-only and both params), but you can see that there can be way more with a normal world search. - Noone likes to concatenate strings! Another option is to query a large subset of the data and then narrow it down in memory. This is particularly useful if you are working with a definite subset of the data, like all the dogs in a city. You know there are a lot but you also know there aren't that many... so your CityDog search page can load all the dogs for the city in memory, which is a single pre-compiled query and then refine the results protected List<Dod> GetSomeDogs( string name, int age, string city) { string query = "select value dog from Entities.DogSet where dog.Owner.Address.City == @City "; ObjectQuery<Dog> oQuery = new ObjectQuery<Dog>( query, YourContext ); oQuery.Parameters.Add( new ObjectParameter( "City", city ) ); List<Dog> dogs = oQuery.ToList(); if( !String.IsNullOrEmpty(name) ) dogs = dogs.Where( it => it.Name == name ); if( age > 0 ) dogs = dogs.Where( it => it.Age == age ); return dogs; } It is particularly useful when you start displaying all the data then allow for filtering. Problems: - Could lead to serious data transfer if you are not careful about your subset. - You can only filter on the data that you returned. It means that if you don't return the Dog.Owner association, you will not be able to filter on the Dog.Owner.Name So what is the best solution? There isn't any. You need to pick the solution that works best for you and your problem: - Use lambda-based query building when you don't care about pre-compiling your queries. - Use fully-defined pre-compiled Linq query when your object structure is not too complex. - Use EntitySQL/string concatenation when the structure could be complex and when the possible number of different resulting queries are small (which means fewer pre-compilation hits). - Use in-memory filtering when you are working with a smallish subset of the data or when you had to fetch all of the data on the data at first anyway (if the performance is fine with all the data, then filtering in memory will not cause any time to be spent in the db). Singleton access The best way to deal with your context and entities accross all your pages is to use the singleton pattern: public sealed class YourContext { private const string instanceKey = "On3GoModelKey"; YourContext(){} public static YourEntities Instance { get { HttpContext context = HttpContext.Current; if( context == null ) return Nested.instance; if (context.Items[instanceKey] == null) { On3GoEntities entity = new On3GoEntities(); context.Items[instanceKey] = entity; } return (YourEntities)context.Items[instanceKey]; } } class Nested { // Explicit static constructor to tell C# compiler // not to mark type as beforefieldinit static Nested() { } internal static readonly YourEntities instance = new YourEntities(); } } NoTracking, is it worth it? When executing a query, you can tell the framework to track the objects it will return or not. What does it mean? With tracking enabled (the default option), the framework will track what is going on with the object (has it been modified? Created? Deleted?) and will also link objects together, when further queries are made from the database, which is what is of interest here. For example, lets assume that Dog with ID == 2 has an owner which ID == 10. Dog dog = (from dog in YourContext.DogSet where dog.ID == 2 select dog).FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; Person owner = (from o in YourContext.PersonSet where o.ID == 10 select dog).FirstOrDefault(); //dog.OwnerReference.IsLoaded == true; If we were to do the same with no tracking, the result would be different. ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>) (from dog in YourContext.DogSet where dog.ID == 2 select dog); oDogQuery.MergeOption = MergeOption.NoTracking; Dog dog = oDogQuery.FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; ObjectQuery<Person> oPersonQuery = (ObjectQuery<Person>) (from o in YourContext.PersonSet where o.ID == 10 select o); oPersonQuery.MergeOption = MergeOption.NoTracking; Owner owner = oPersonQuery.FirstOrDefault(); //dog.OwnerReference.IsLoaded == false; Tracking is very useful and in a perfect world without performance issue, it would always be on. But in this world, there is a price for it, in terms of performance. So, should you use NoTracking to speed things up? It depends on what you are planning to use the data for. Is there any chance that the data your query with NoTracking can be used to make update/insert/delete in the database? If so, don't use NoTracking because associations are not tracked and will causes exceptions to be thrown. In a page where there are absolutly no updates to the database, you can use NoTracking. Mixing tracking and NoTracking is possible, but it requires you to be extra careful with updates/inserts/deletes. The problem is that if you mix then you risk having the framework trying to Attach() a NoTracking object to the context where another copy of the same object exist with tracking on. Basicly, what I am saying is that Dog dog1 = (from dog in YourContext.DogSet where dog.ID == 2).FirstOrDefault(); ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>) (from dog in YourContext.DogSet where dog.ID == 2 select dog); oDogQuery.MergeOption = MergeOption.NoTracking; Dog dog2 = oDogQuery.FirstOrDefault(); dog1 and dog2 are 2 different objects, one tracked and one not. Using the detached object in an update/insert will force an Attach() that will say "Wait a minute, I do already have an object here with the same database key. Fail". And when you Attach() one object, all of its hierarchy gets attached as well, causing problems everywhere. Be extra careful. How much faster is it with NoTracking It depends on the queries. Some are much more succeptible to tracking than other. I don't have a fast an easy rule for it, but it helps. So I should use NoTracking everywhere then? Not exactly. There are some advantages to tracking object. The first one is that the object is cached, so subsequent call for that object will not hit the database. That cache is only valid for the lifetime of the YourEntities object, which, if you use the singleton code above, is the same as the page lifetime. One page request == one YourEntity object. So for multiple calls for the same object, it will load only once per page request. (Other caching mechanism could extend that). What happens when you are using NoTracking and try to load the same object multiple times? The database will be queried each time, so there is an impact there. How often do/should you call for the same object during a single page request? As little as possible of course, but it does happens. Also remember the piece above about having the associations connected automatically for your? You don't have that with NoTracking, so if you load your data in multiple batches, you will not have a link to between them: ObjectQuery<Dog> oDogQuery = (ObjectQuery<Dog>)(from dog in YourContext.DogSet select dog); oDogQuery.MergeOption = MergeOption.NoTracking; List<Dog> dogs = oDogQuery.ToList(); ObjectQuery<Person> oPersonQuery = (ObjectQuery<Person>)(from o in YourContext.PersonSet select o); oPersonQuery.MergeOption = MergeOption.NoTracking; List<Person> owners = oPersonQuery.ToList(); In this case, no dog will have its .Owner property set. Some things to keep in mind when you are trying to optimize the performance. No lazy loading, what am I to do? This can be seen as a blessing in disguise. Of course it is annoying to load everything manually. However, it decreases the number of calls to the db and forces you to think about when you should load data. The more you can load in one database call the better. That was always true, but it is enforced now with this 'feature' of EF. Of course, you can call if( !ObjectReference.IsLoaded ) ObjectReference.Load(); if you want to, but a better practice is to force the framework to load the objects you know you will need in one shot. This is where the discussion about parametrized Includes begins to make sense. Lets say you have you Dog object public class Dog { public Dog Get(int id) { return YourContext.DogSet.FirstOrDefault(it => it.ID == id ); } } This is the type of function you work with all the time. It gets called from all over the place and once you have that Dog object, you will do very different things to it in different functions. First, it should be pre-compiled, because you will call that very often. Second, each different pages will want to have access to a different subset of the Dog data. Some will want the Owner, some the FavoriteToy, etc. Of course, you could call Load() for each reference you need anytime you need one. But that will generate a call to the database each time. Bad idea. So instead, each page will ask for the data it wants to see when it first request for the Dog object: static public Dog Get(int id) { return GetDog(entity,"");} static public Dog Get(int id, string includePath) { string query = "select value o " + " from YourEntities.DogSet as o " +

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  • Passing parameters between Silverlight and ASP.NET – Part 1

    - by mohanbrij
    While working with Silverlight applications, we may face some scenarios where we may need to embed Silverlight as a component, like for e.g in Sharepoint Webpars or simple we can have the same with ASP.NET. The biggest challenge comes when we have to pass the parameters from ASP.NET to Silverlight components or back from Silverlight to ASP.NET. We have lots of ways we can do this, like using InitParams, QueryStrings, using HTML objects in Silverlight, etc. All these different techniques have some advantages or disadvantages or limitations. Lets see one by one why we should choose one and what are the ways to achieve the same. 1. InitParams: Lets start with InitParams, Start your Visual Studio 2010 IDE, and Create a Silverlight Application, give any name. Now go to the ASP.NET WebProject which is used to Host the Silverlight XAP component. You will find lots of different tags are used by Silverlight object as <params> tags. To use InitParams, Silverlight provides us with a tag called InitParams which we can use to pass parameters to Silverlight object from ASP.NET. 1: <object data="data:application/x-silverlight-2," type="application/x-silverlight-2" width="100%" height="100%"> 2: <param name="source" value="ClientBin/SilverlightApp.xap"/> 3: <param name="onError" value="onSilverlightError" /> 4: <param name="background" value="white" /> 5: <param name="minRuntimeVersion" value="4.0.50826.0" /> 6: <param name="initparams" id="initParams" runat="server" value=""/> 7: <param name="autoUpgrade" value="true" /> 8: <a href="http://go.microsoft.com/fwlink/?LinkID=149156&v=4.0.50826.0" style="text-decoration:none"> 9: <img src="http://go.microsoft.com/fwlink/?LinkId=161376" alt="Get Microsoft Silverlight" style="border-style:none"/> 10: </a> 11: </object> Here in the code above I have included a initParam as a param tag (line 6), now in the page load I will add a line 1: initParams.Attributes.Add("value", "key1=Brij, key2=Mohan"); This basically add a value parameter inside the initParam. So thats all we need in our ASP.NET side, now coming to the Silverlight Code open the code behind of App.xaml and add the following lines of code. 1: private string firstKey, secondKey; 2: private void Application_Startup(object sender, StartupEventArgs e) 3: { 4: if (e.InitParams.ContainsKey("key1")) 5: this.firstKey = e.InitParams["key1"]; 6: if (e.InitParams.ContainsKey("key2")) 7: this.secondKey = e.InitParams["key2"]; 8: this.RootVisual = new MainPage(firstKey, secondKey); 9: } This code fetch the init params and pass it to our MainPage.xaml constructor, in the MainPage.xaml we can use these variables according to our requirement, here in this example I am simply displaying the variables in a Message Box. 1: public MainPage(string param1, string param2) 2: { 3: InitializeComponent(); 4: MessageBox.Show("Welcome, " + param1 + " " + param2); 5: } This will give you a sample output as Limitations: Depending on the browsers you have some limitation on the overall string length of the parameters you can pass. To get more details on this limitation, you can refer to this link :http://www.boutell.com/newfaq/misc/urllength.html 2. QueryStrings To show this example I am taking the scenario where we have a default.aspx page and we are going to the SIlverlightTestPage.aspx, and we have to work with the parameters which was passed by default.aspx in the SilverlightTestPage.aspx Silverlight Component. So first I will add a new page in my application which contains a button with ID =btnNext, and on click of the button I will redirect my page to my SilverlightTestAppPage.aspx with the required query strings. Code of Default.aspx 1: protected void btnNext_Click(object sender, EventArgs e) 2: { 3: Response.Redirect("~/SilverlightAppTestPage.aspx?FName=Brij" + "&LName=Mohan"); 4: } Code of MainPage.xaml.cs 1: public partial class MainPage : UserControl 2: { 3: public MainPage() 4: { 5: InitializeComponent(); 6: this.Loaded += new RoutedEventHandler(MainPage_Loaded); 7: } 8: 9: void MainPage_Loaded(object sender, RoutedEventArgs e) 10: { 11: IDictionary<string, string> qString = HtmlPage.Document.QueryString; 12: string firstName = string.Empty; 13: string lastName = string.Empty; 14: foreach (KeyValuePair<string, string> keyValuePair in qString) 15: { 16: string key = keyValuePair.Key; 17: string value = keyValuePair.Value; 18: if (key == "FName") 19: firstName = value; 20: else if (key == "LName") 21: lastName = value; 22: } 23: MessageBox.Show("Welcome, " + firstName + " " + lastName); 24: } 25: } Set the Startup page as Default.aspx, now run the application. This will give you the following output: Since here also you are using the Query Strings to pass your parameters, so you are depending on the browser capabilities of the length of the query strings it can pass. Here also you can refer the limitation which I have mentioned in my previous example for the length of parameters you can use.   3. Using HtmlPage.Document Silverlight to ASP.NET <—> ASP.NET to Silverlight: To show this I setup a sample Silverlight Application with Buttons Get Data and Set Data with the Data Text Box. In ASP.NET page I kep a TextBox to Show how the values passed to and From Silverlight to ASP.NET reflects back. My page with Silverlight control looks like this. When I Say Get Data it pulls the data from ASP.NET to Silverlight Control Text Box, and When I say Set data it basically Set the Value from Silverlight Control TextBox to ASP.NET TextBox. Now let see the code how it is doing. This is my ASP.NET Source Code. Here I have just created a TextBox named : txtData 1: <body> 2: <form id="form1" runat="server" style="height:100%"> 3: <div id="silverlightControlHost"> 4: ASP.NET TextBox: <input type="text" runat="server" id="txtData" value="Some Data" /> 5: <object data="data:application/x-silverlight-2," type="application/x-silverlight-2" width="100%" height="100%"> 6: <param name="source" value="ClientBin/SilverlightApplication1.xap"/> 7: <param name="onError" value="onSilverlightError" /> 8: <param name="background" value="white" /> 9: <param name="minRuntimeVersion" value="4.0.50826.0" /> 10: <param name="autoUpgrade" value="true" /> 11: <a href="http://go.microsoft.com/fwlink/?LinkID=149156&v=4.0.50826.0" style="text-decoration:none"> 12: <img src="http://go.microsoft.com/fwlink/?LinkId=161376" alt="Get Microsoft Silverlight" style="border-style:none"/> 13: </a> 14: </object><iframe id="_sl_historyFrame" style="visibility:hidden;height:0px;width:0px;border:0px"></iframe> 15: </div> 16: </form> 17: </body> My actual logic for getting and setting the data lies in my Silverlight Control, this is my XAML code with TextBox and Buttons. 1: <Grid x:Name="LayoutRoot" Background="White" Height="100" Width="450" VerticalAlignment="Top"> 2: <Grid.ColumnDefinitions> 3: <ColumnDefinition Width="110" /> 4: <ColumnDefinition Width="110" /> 5: <ColumnDefinition Width="110" /> 6: <ColumnDefinition Width="110" /> 7: </Grid.ColumnDefinitions> 8: <TextBlock Text="Silverlight Text Box: " Grid.Column="0" VerticalAlignment="Center"></TextBlock> 9: <TextBox x:Name="DataText" Width="100" Grid.Column="1" Height="20"></TextBox> 10: <Button x:Name="GetData" Width="100" Click="GetData_Click" Grid.Column="2" Height="30" Content="Get Data"></Button> 11: <Button x:Name="SetData" Width="100" Click="SetData_Click" Grid.Column="3" Height="30" Content="Set Data"></Button> 12: </Grid> Now we have to write few lines of Button Events for Get Data and Set Data which basically make use of Windows.System.Browser namespace. 1: private void GetData_Click(object sender, RoutedEventArgs e) 2: { 3: DataText.Text = HtmlPage.Document.GetElementById("txtData").GetProperty("value").ToString(); 4: } 5:  6: private void SetData_Click(object sender, RoutedEventArgs e) 7: { 8: HtmlPage.Document.GetElementById("txtData").SetProperty("value", DataText.Text); 9: } That’s it so when we run this application my Form will look like this. 4. Using Object Serialization. This is a useful when we want to pass Objects of Data from our ASP.NET application to Silverlight Controls and back. This technique basically uses the above technique I mentioned in Pint 3 above. Since this itself is a length topic so details of this I am going to cover in Part 2 of this Post with Sample Code Example very soon.

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  • how to update child records when updating the Master table using Linq [closed]

    - by user20358
    I currently use a general repositry class that can update only a single table like so public abstract class MyRepository<T> : IRepository<T> where T : class { protected IObjectSet<T> _objectSet; protected ObjectContext _context; public MyRepository(ObjectContext Context) { _objectSet = Context.CreateObjectSet<T>(); _context = Context; } public IQueryable<T> GetAll() { return _objectSet.AsQueryable(); } public IQueryable<T> Find(Expression<Func<T, bool>> filter) { return _objectSet.Where(filter); } public void Add(T entity) { _objectSet.AddObject(entity); _context.ObjectStateManager.ChangeObjectState(entity, System.Data.EntityState.Added); _context.SaveChanges(); } public void Update(T entity) { _context.ObjectStateManager.ChangeObjectState(entity, System.Data.EntityState.Modified); _context.SaveChanges(); } public void Delete(T entity) { _objectSet.Attach(entity); _context.ObjectStateManager.ChangeObjectState(entity, System.Data.EntityState.Deleted); _objectSet.DeleteObject(entity); _context.SaveChanges(); } } For every table class generated by my EDMX designer I create another class like this public class CustomerRepo : MyRepository<Customer> { public CustomerRepo (ObjectContext context) : base(context) { } } for any updates that I need to make to a particular table I do this: Customer CustomerObj = new Customer(); CustomerObj.Prop1 = ... CustomerObj.Prop2 = ... CustomerObj.Prop3 = ... CustomerRepo.Update(CustomerObj); This works perfectly well when I am updating just to the specific table called Customer. Now if I need to also update each row of another table which is a child of Customer called Orders what changes do I need to make to the class MyRepository. Orders table will have multiple records for a Customer record and multiple fields too, say for example Field1, Field2, Field3. So my questions are: 1.) If I only need to update Field1 of the Orders table for some rows based on a condition and Field2 for some other rows based on a different condition then what changes I need to do? 2.) If there is no such condition and all child rows need to be updated with the same value for all rows then what changes do I need to do? Thanks for taking the time. Look forward to your inputs...

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  • Installing .NET Framework 4 Client Profile breaks Windows Update

    - by Richard
    I have a Samsung NC-10 netbook with a fresh install of Windows 7 Home Premium 32-bit (it only had 2GB). If Microsoft .NET Framework 4 Client Profile is installed on it, Windows Update will always return error code 8024402F ("Windows Update encountered an unknown error"). As soon as I uninstall it, Windows Update works just fine again. Out of the four computers in this house, only this netbook has the problem. My question is: How can I get the .NET Framework 4 Client Profile installed on my netbook and continue to have a functioning Windows Update? ----- More information ----- The hard-drive recently died on my netbook so I replaced it with a nice new SSD and did a fresh installation of Windows 7 Home Premium (SP1) - along with all the updates. At some point I found that, when I ran Windows Update, I was greeted with error code 8024402F ("Windows Update encountered an unknown error"). Looking in C:\Windows\WindowsUpdate.log, I saw the following issue: WARNING: ECP: Failed to validate cab file digest downloaded from http://download.windowsupdate.com/msdownload/update/software/dflt/2012/02/4913552_4a5c9563d1f58c77f30d0d5c9999e4b8bff3ab21.cab with error 0x80091007 WARNING: ECP: This roundtrip contained some optimized updates which failed. New Update count = 0, Old Count = 3 FATAL: ProcessCoreMetadata did not return any update to be committed WARNING: Sync of Updates: 0x8024402f WARNING: SyncServerUpdatesInternal failed: 0x8024402f When I downloaded the CAB from the URL listed and opened it, it contained a file called 4913552.txt. A search on Google suggested that it's related to Microsoft .NET Framework 4 Client Profile. Other people had reported problems with it breaking Windows Update, but they were running Windows XP. I tried the steps outlined on the Microsoft site for this error code, but it reported that there was nothing wrong. I also found this superuser question, I tried all the answers listed but none of them made any difference. My router doesn't block ActiveX, changing my internet settings in IE made no difference, assuming it was a corrupted update repository didn't do anything (except wipe my update history), my date and time was correct, switching to Google's DNS didn't work and neither did disabling IPv6. Figuring that this update was corrupted, I repaired it and nothing changed. In desperation I un-installed it and Windows Update started working again! Brilliant! I then downloaded the full version from the Microsoft website, installed it and, thankfully, Windows Update continued to work just fine. A week later I turn on my netbook and Windows Update is broken again with exactly the same error message and log entries as before. Repairing .NET Framework 4 Client Profile did nothing, removing it entirely solved the problem again. Thinking this might be some odd Windows installation issue, I formatted the hard-drive and re-installed Windows. Same problem as before - as soon as .NET Framework 4 Client Profile ended up on the netbook, Windows Update stopped working and reported error 8024402F. As soon as it was un-installed, everything worked just fine again. There are three other machines in this house and all of them have working Windows Update and this Client Profile. Does anyone know why it causes this netbook to break and, more importantly, how I can fix it?

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  • WCF data services (OData), query with inheritance limitation?

    - by Mathieu Hétu
    Project: WCF Data service using internally EF4 CTP5 Code-First approach. I configured entities with inheritance (TPH). See previous question on this topic: Previous question about multiple entities- same table The mapping works well, and unit test over EF4 confirms that queries runs smoothly. My entities looks like this: ContactBase (abstract) Customer (inherits from ContactBase), this entity has also several Navigation properties toward other entities Resource (inherits from ContactBase) I have configured a discriminator, so both Customer and Resource map to the same table. Again, everythings works fine on the Ef4 point of view (unit tests all greens!) However, when exposing this DBContext over WCF Data services, I get: - CustomerBases sets exposed (Customers and Resources sets seems hidden, is it by design?) - When I query over Odata on Customers, I get this error: Navigation Properties are not supported on derived entity types. Entity Set 'ContactBases' has a instance of type 'CodeFirstNamespace.Customer', which is an derived entity type and has navigation properties. Please remove all the navigation properties from type 'CodeFirstNamespace.Customer'. Stacktrace: at System.Data.Services.Serializers.SyndicationSerializer.WriteObjectProperties(IExpandedResult expanded, Object customObject, ResourceType resourceType, Uri absoluteUri, String relativeUri, SyndicationItem item, DictionaryContent content, EpmSourcePathSegment currentSourceRoot) at System.Data.Services.Serializers.SyndicationSerializer.WriteEntryElement(IExpandedResult expanded, Object element, ResourceType expectedType, Uri absoluteUri, String relativeUri, SyndicationItem target) at System.Data.Services.Serializers.SyndicationSerializer.<DeferredFeedItems>d__b.MoveNext() at System.ServiceModel.Syndication.Atom10FeedFormatter.WriteItems(XmlWriter writer, IEnumerable`1 items, Uri feedBaseUri) at System.ServiceModel.Syndication.Atom10FeedFormatter.WriteFeedTo(XmlWriter writer, SyndicationFeed feed, Boolean isSourceFeed) at System.ServiceModel.Syndication.Atom10FeedFormatter.WriteFeed(XmlWriter writer) at System.ServiceModel.Syndication.Atom10FeedFormatter.WriteTo(XmlWriter writer) at System.Data.Services.Serializers.SyndicationSerializer.WriteTopLevelElements(IExpandedResult expanded, IEnumerator elements, Boolean hasMoved) at System.Data.Services.Serializers.Serializer.WriteRequest(IEnumerator queryResults, Boolean hasMoved) at System.Data.Services.ResponseBodyWriter.Write(Stream stream) Seems like a limitation of WCF Data services... is it? Not much documentation can be found on the web about WCF Data services (OData) and inheritance specifications. How can I overpass this exception? I need these navigation properties on derived entities, and inheritance seems the only way to provide mapping of 2 entites on the same table with Ef4 CTP5... Any thoughts?

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  • Entity Framework many-to-many using VB.Net Lambda

    - by bgs264
    Hello, I'm a newbie to StackOverflow so please be kind ;) I'm using Entity Framework in Visual Studio 2010 Beta 2 (.NET framework 4.0 Beta 2). I have created an entity framework .edmx model from my database and I have a handful of many-to-many relationships. A trivial example of my database schema is Roles (ID, Name, Active) Members (ID, DateOfBirth, DateCreated) RoleMembership(RoleID, MemberID) I am now writing the custom role provider (Inheriting System.Configuration.Provider.RoleProvider) and have come to write the implementation of IsUserInRole(username, roleName). The LINQ-to-Entity queries which I wrote, when SQL-Profiled, all produced CROSS JOIN statements when what I want is for them to INNER JOIN. Dim query = From m In dc.Members From r In dc.Roles Where m.ID = 100 And r.Name = "Member" Select m My problem is almost exactly described here: http://stackoverflow.com/questions/553918/entity-framework-and-many-to-many-queries-unusable I'm sure that the solution presented there works well, but whilst I studied Java at uni and I can mostly understand C# I cannot understand this Lambda syntax provided and I need to get a similar example in VB. I've looked around the web for the best part of half a day but I'm not closer to my answer. So please can somebody advise how, in VB, I can construct a LINQ statement which would do this equivalent in SQL: SELECT rm.RoleID FROM RoleMembership rm INNER JOIN Roles r ON r.ID = rm.RoleID INNER JOIN Members m ON m.ID = rm.MemberID WHERE r.Name = 'Member' AND m.ID = 101 I would use this query to see if Member 101 is in Role 3. (I appreciate I probably don't need the join to the Members table in SQL but I imagine in LINQ I'd need to bring in the Member object?) UPDATE: I'm a bit closer by using multiple methods: Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim count As Integer Using dc As New CBLModel.CBLEntities Dim persons = dc.Members.Where(AddressOf myTest) count = persons.Count End Using System.Diagnostics.Debugger.Break() End Sub Function myTest(ByVal m As Member) As Boolean Return m.ID = "100" AndAlso m.Roles.Select(AddressOf myRoleTest).Count > 0 End Function Function myRoleTest(ByVal r As Role) As Boolean Return r.Name = "Member" End Function SQL Profiler shows this: SQL:BatchStarting SELECT [Extent1].[ID] AS [ID], ... (all columns from Members snipped for brevity) ... FROM [dbo].[Members] AS [Extent1] RPC:Completed exec sp_executesql N'SELECT [Extent2].[ID] AS [ID], [Extent2].[Name] AS [Name], [Extent2].[Active] AS [Active] FROM [dbo].[RoleMembership] AS [Extent1] INNER JOIN [dbo].[Roles] AS [Extent2] ON [Extent1].[RoleID] = [Extent2].[ID] WHERE [Extent1].[MemberID] = @EntityKeyValue1',N'@EntityKeyValue1 int',@EntityKeyValue1=100 SQL:BatchCompleted SELECT [Extent1].[ID] AS [ID], ... (all columns from Members snipped for brevity) ... FROM [dbo].[Members] AS [Extent1] I'm not certain why it is using sp_execsql for the inner join statement and why it's still running a select to select ALL members though. Thanks. UPDATE 2 I've written it by turning the above "multiple methods" into lambda expressions then all into one query, like this: Dim allIDs As String = String.Empty Using dc As New CBLModel.CBLEntities For Each retM In dc.Members.Where(Function(m As Member) m.ID = 100 AndAlso m.Roles.Select(Function(r As Role) r.Name = "Doctor").Count > 0) allIDs &= retM.ID.ToString & ";" Next End Using But it doesn't seem to work: "Doctor" is not a role that exists, I just put it in there for testing purposes, yet "allIDs" still gets set to "100;" The SQL in SQL Profiler this time looks like this: SELECT [Project1].* FROM ( SELECT [Extent1].*, (SELECT COUNT(1) AS [A1] FROM [dbo].[RoleMembership] AS [Extent2] WHERE [Extent1].[ID] = [Extent2].[MemberID]) AS [C1] FROM [dbo].[Members] AS [Extent1] ) AS [Project1] WHERE (100 = [Project1].[ID]) AND ([Project1].[C1] > 0) For brevity I turned the list of all the columns from the Members table into * As you can see it's just ignoring the "Role" query... :/

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