Entity Framework 6 - Knowledge Base (KB)
5242 results in tag: entity-framework
LINQ to SQL vs. Entity Framework
Now that .NET v3.5 SP1 has been released (along with VS2008 SP1), we now have access to the .NET entity framework....My question is this. When trying to decide between using the Entity Framework and LINQ to SQL as an ORM, what's the difference?...The way...
asked by Chris Roberts
Expression. How do I invoke Entity Framework?
The Entity Framework does not support the ...Expression.Invoke... operator. You receive the following exception when trying to use it:..."The LINQ expression node type 'Invoke' is not supported in LINQ to Entities....Has anyone got a workaround for this ...
asked by Brad Leach
In Entity Framework, update the database schema.
I installed VS SP1 and played around with Entity Framework....I created a schema from an existing database and tried some basic operations....Most of it went well, except the database schema update....I changed the database in every basic way:...added a n...
asked by Biri
Entity Framework for ADO.NET tutorials
Does anyone know of any good tutorials on ADO.NET Entity Framework?...There are a few useful links here at ...Stack OverFlow..., and I've found one tutorial at ...Jason's DotNet Architecture Blog..., but can anyone recommend any other good tutorials? Any...
asked by Yngvar Johnsen
Using Entity Framework with MySQL
Can't find anything relevant about Entity Framework/MySQL on Google so I'm hoping someone knows about it.
asked by vintana
Is Microsoft Entity Framework compatible with Oracle?
Is it possible to use Microsoft Entity Framework with Oracle database?
asked by Xerx
Identity columns with ADO.NET Entity Framework
Is the Entity Framework aware of identity columns? ...I am using SQL Server 2005 Express Edition and have several tables where the primary key is an identity column. when I use these tables to create an entity model and use the model in conjunction with a...
asked by matthew thomas
How to use the Entity Framework to connect items from different contexts.
I am ...very... new to the entity framework, so please bear with me......How can I relate two objects from different contexts together?...The example below throws the following exception:...System.InvalidOperationException: The relationship between the ...
asked by Giovanni Galbo
What are some alternatives to expanding in a LINQ to ADO.net Data Service query?
I am wondering if there are any alternatives to using the Expand key word when performing an LINQ to ADO.net Data Services query. The expand method does get me the data I am interested in, but it requires me to know all of the sub-objects that I am going...
asked by ChrisHDog
Validation of Entity Framework
I'm getting ready to start a new project and I've been researching the entity framework. My question is what is the best strategy for validating the entities? Other projects I've worked on have used attributes for most of the validation, but obviously thi...
asked by Micah
How can I use the Entity Framework to establish foreign key relationships?
I want to create a new row in my database on a table that has a couple of foreign key relationships and I haven't been able to get a handle on what order and what calls need to be made. This is what I have so far:...db.Models.Order order = DB.Models.Order...
asked by Jared
Using entities from Entity Framework as business objects?
I'm using Entity Framework O/R mapper from Microsoft and using entity classes (generated classes that are mapped to DB objects) as a business objects. Is this OK? Please state your cons or pros. What to do in a case of WCF communication between business ...
asked by Aleksandar
What is the best way to create a Linq Expression Tree that compares to a generic object?
I have an IQueryable and an object of type T....I want to do IQueryable().Where(o => o.GetProperty(fieldName) == objectOfTypeT.GetProperty(fieldName))...so ......public IQueryable<T> DoWork<T>(string fieldName) where T : EntityObject { ... T...
asked by JTew
Performance of Linq To SQL versus Entity Framework
I have been searching for recent performance benchmarks that compare L2S and EF and couldnt find any that tested calling stored procedures using the released version of EF. So, I ran some of my own tests and found some interesting results....Do these resu...
asked by Vyrotek
How can I utilize LINQ to Entities with a WPF TreeView HierarchicalDataTemplate?
I've got a Page class in my .edmx ADO.NET Entity Data Model file with with Parent and Children properties. It's for a hierarchy of Pages....removed dead ImageShack link - ADO.NET Entity Framework Hierarchical Page Class...This is handled in my SQL databa...
asked by Zack Peterson
TreeView Binding in WPF
I've got a class with Parent and Children properties....ADO.NET Entity Framework Hierarchical Page Class http://img148.imageshack.us/img148/6802/edmxxe8.gif...I want to display this hierarchy in a WPF treeview....Here's my XAML......<TreeView Margin="12" ...
asked by Zack Peterson
Entity Framework tracks every data update.
There is a need from a customer to log every data change to a logging table with the actual user who made the modification. The application is using one SQL user to access the database, but we need to log the "real" user id....We can do this in t-sql by w...
asked by Biri
Within a generic extension method, how do I apply OrderBy to an IQueryable using a string column name?
public static IQueryable<TResult> ApplySortFilter<T, TResult>(this IQueryable<T> query, string columnName) where T : EntityObject { var param = Expression.Parameter(typeof(T), "o"); var body = Expression.PropertyOrField(param,columnName); var sor...
asked by JTew
With Linq to Entity, how do I obtain the maximum ID?
I have a table User which has an identity column ...UserID..., now what is the correct Linq to Entity line of code that would return me the max ...UserID...?...I've tried:...using (MyDBEntities db = new MyDBEntities()) { var User = db.Users.Last(); ...
asked by Ray
ADO.NET Entity Framework and TDD
I've been playing with ADO.NET Entity Framework lately, and I find that it suits my needs for a project I'm developing. I also find cool its non-invasive nature....After generating a data model from an existing database you are faced with the task of inte...
asked by Dario Solera
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