Entity Framework 6 - Knowledge Base (KB)
792 results in tag: .net
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
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
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
Entity Framework could not be saved. Inherited characteristics
I have implemented some table-per-type inheritance in my data model (basically have a ...BaseEntity... type with all the base information for my items and a ...Employer... type that inherits from the ...BaseEntity... item). Everything appears to be set u...
asked by ChrisHDog
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
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
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
Entity Framework Join and Include
I have the following query of linq to entities. The problem is that it doesn't seem to load the "Tags" relation even though i have included a thing for it. It works fine if i do not join on tags but i need to do that.... var items = from i in d...
asked by Olaj
Creating an Entity Framework 1:1 relationship
I'm trying to define a 1:1 association between two entities (one maps to a table and the other to a view - using DefinedQuery) in an Entity Framework model. When trying to define the mapping for this in the designer, it makes me choose the (1) table or v...
asked by Craig Fisher
When to Avoid Using Entity Framework
I have been playing around with the EF to see what it can handle. Also many articles and posts explain the various scenarios in which the EF can be used, however if miss the "con" side somehow. Now my question is, ...in what kind of scenarios should I sta...
asked by driAn
The Update Wizard in ADO.NET Entity Framework does not add tables.
I ...added a new ADO.Net Entity Data Model... into my project and used the ...Update Wizard... to add tables into the model. Five of the selected tables were added to the design surface. Two other tables will not add. I select them in the wizard and cl...
asked by Robert Claypool
ADO.NET Entity Framework Stored Procedures
I'm trying to use a stored procedure in the entity framework. I had the model created initially without the stored proc. I then went into Update Model from Database and selected the stored procedure I wanted and then added it through the function import. ...
asked by Satish
Is Entity Framework and a large number of queries unusable?
I'm trying EF out and I do a lot of filtering based on many to many relationships. For instance I have persons, locations and a personlocation table to link the two. I also have a role and personrole table. ...EDIT: Tables: Person (personid, name) Perso...
asked by John Landheer
Entity Model Function Imports with a Non-Entity Return Type
I have a stored procedure in my Entity Data Model and added it to the function imports....Problem is... Visual Studio generates the function code in the model's code-behind if and only if I specify the return to be an entity type. ...Scalar and null retu...
asked by Robert Claypool
In Entity Framework, how can I utilize the default column value from a DataBase?
I have a Date column in table which has default value or binding as getutcdate(). I want to use this in entity framework.On generating EDM I was able to find "Default Value " property at column level but I think it is for hardcoded value. ...Please let me...
asked by Mak
