Entity Framework 6 - Knowledge Base (KB)
6940 results
"The underlying supplier failed on Open," says the Entity Framework error.
I have a test. What happens is that whenever test1 is executed first, test2 fails with the message:..."System.Data.EntityException : System.Data.EntityException : the underlying provider failed on open. cannot open database "DBEntities" requ...
asked by Attilah
Incredibly similar query in Entity Framework
My SQL query against a particular view returns me 3 different rows.... select * from vwSummary where vidate >= '10-15-2010' and vidate <= '10-15-2010' and idno = '0330' order by viDate ...But if i run the same query through my entity framework, I get 3...
asked by franklins
In entity framework 3.5, you may refresh a stored method.
I am using .NET 3.5 SP1, VS 2008 with the entity framework. I originally added a stored procedure to my model which took 2 parameters. Later, I changed the sproc to just take 1 parameter. I ran the ...Update Model From Database... menu option and confirme...
asked by Jeff
First, create an index using entity framework code (CTP5)
Is there a way to get EF CTP5 to create an index when it creates a schema?...Update:... See ...here... for how EF 6.1 handles this (as pointed out by ...juFo... below).
asked by Sean Kearon
Entityframework Join using lambdas and the join method
It seems there are different ways to do joins using linq. One is more straightforward and involves just joining tables like this:...var found = from c in s.categories join cm in s.categorymaps on c.CategoryId equals cm.ChildCategoryId ...
asked by Mason
In Entity Framework, how do you change an object?
DataContext.ApplyCurrentValues() needs entitySetName, what is it?...I think that code would same:... public void Edit(Products p) { DataContext.ApplyCurrentValues("Products", p); DataContext.SaveChanges(); } ...Is it correct?
asked by FreeVice
Databinding using Entity Framework 4 on WinForms ComboBoxes with Foreign Keys
I am using Entity Framework 4, I need to get WinForms to bind Customers and Quotes as a Master - Detail relationship....I have a Quote table which I lay out as details view on a Windows Form....The quote table has 3 foreign keys to the customer table. (fi...
asked by Andrew Roberts
Creating a new DbEntityEntry or mocking or simulating a DbEntityEntry
Following on the heels of my other ...question about mocking DbContext.Set... I've got another question about mocking EF Code First....I now have a method for my update that looks like:...if (entity == null) throw new ArgumentNullException("entity"); ...
asked by taylonr
Property StoreGeneratedPattern="Computed" in Entity Framework
I have a ...DateTime... property. I need this property's default value to be ...DateTime.Now.... And then I found out that you can specify an attribute ...StoreGeneratedPattern="Computed"... and set it to ...(getdate())... in SQL. This works successfully....
asked by ebattulga
Creating an interface using Entity Framework
I want to use IoC with Entity framework and Ninject. I figure I need the Generated Entity classes to implement an interface, ICRUD. There's a ...walkthrough... that shows how to force Entity framework to implement an interface. I followed the direction...
asked by P.Brian.Mackey
Code First Memory Usage in ASP.NET MVC and EF
I have an application built in ASP.NET MVC 3 that uses SQL CE for storage and EF CTP 5 for data access....I've deployed this site to a shared host only to find that it is constantly being recycled as it's hitting the 100mb limit they set on their (dedicat...
asked by Ben Foster
"CategoryCategoryID" is an incorrect column name in the EF Code.
There is a existing database named Northwind with a webform application. when running the application raise up a error: 'invalid column name CategoryCategoryID'. any one help me?. thanks in advance!!...Category.cs:...public class Category { public in...
asked by user441222
In an Asp.Net MVC 3 application, how can I collect complicated child objects?
I want to be able to update a model and all its collections of child objects in the same view. I have been referred to these examples: ...http://haacked.com/archive/2008/10/23/model-binding-to-a-list.aspx... and ...http://blog.stevensanderson.com/2010/01/...
asked by Anders
Entity to Linq AcceptAllChanges SaveChanges
What is the difference between the following:... db.AcceptAllChanges(); // vs db.SaveChanges(); db.AddToCustomer() // vs db.Customers.AddObject(Mycustomer); ...and why there is ...db.Customers.DeleteObject(M...
asked by Stacker
Nullable Types and Expression Trees
I've been playing around with Expression Trees. I have the following simple method that performs a query by dynamically creating an Expression Tree. ItemType is a nullable int in the database, ...and also in the EF entity class.... For some reason thou...
asked by Adam Rackis
In Expression Trees, why is a conversion required?
From ...this question... I asked 5 minutes ago, it's clear that the following code throws an exception, stating that ...Unhandled Exception: System.InvalidOperationException: The binary operator Equal is not defined for the types 'System.Nullable`...
asked by Adam Rackis
Using arguments to call a stored procedure
I have a stored procedure that returns a value, not a dataset, and I have problems getting it to work with EF4....I've seen this: ...http://dotnet.dzone.com/news/how-retrieve-stored-procedure...Here is what I did: I added a procedure to the model, and imp...
asked by katit
WPF MVVM modeling using Entity Framework CTP5 Code First
I have my model all setup for my WPF application and working with entity framework ctp5 code first, here's a sample model class:...public class Task { public int ID { get; set; } public int Index { get; set; } public string Content { get; set;...
asked by Chris Klepeis
In the next Entity Framework, choose N+1.
One of the few valid complaints I hear about EF4 vis-a-vis NHibernate is that EF4 is poor at handling lazily loaded collections. For example, on a lazily-loaded collection, if I say:...if (MyAccount.Orders.Count() > 0) ; ...EF will pull the whole collect...
asked by Adam Rackis
Join two tables using LINQ to Entities, then group and total the columns from each tables.
As the title says, my goal is to JOIN two tables (target and transaction) on several columns, then group the result of that join and sum the values of columns from BOTH tables. The following query only allows access to columns from the FIRST table in the ...
asked by Daniel Coffman
