Insert using a foreign key in Entity Framework

c# entity-framework foreign-keys insert-update

Question

Apologies if there is clear answer for this somewhere. But I can't insert into a simple table due to it containing a foreign key.

Task Table

  • TaskId (PK)
  • Description
  • StatusId (FK)

    Into which I try to insert like so:

            Task t = new Task();
            t.Id = 1234;
            t.Title = "foo";
            t.Status = db.Status.ToList().First();
    

    But get an updateException error: A relationship is being added or deleted from an AssociationSet 'FK_Task_Status'. With cardinality constraints, a corresponding 'Task' must also be added or deleted.

    How can I insert into this table?

    Cheers

    ....

    Found my issue....

    My schema was wrong. When I created my foreign key I pointed it to the wrong field. Had a look in SQL profiler, saw this:

    SELECT 1 AS [C1], [Extent1].[Id] AS [Id], [Extent1].[Descr] AS [Descr], [Extent2].[Id] AS [Id1] FROM [dbo].[Status] AS [Extent1] LEFT OUTER JOIN [dbo].[Task] AS [Extent2] ON [Extent1].[Id] = [Extent2].[Id]

    Which should be this (joining on statusId not id):

    SELECT 1 AS [C1], [Extent1].[Id] AS [Id], [Extent1].[Descr] AS [Descr], [Extent2].[Id] AS [Id1] FROM [dbo].[Status] AS [Extent1] LEFT OUTER JOIN [dbo].[Task] AS [Extent2] ON [Extent1].[Id] = [Extent2].[StatusId]

    Silly me ;)

  • 1
    4
    4/12/2010 4:44:42 PM

    Popular Answer

    in .net framework 4.0 u can use this simple way:

     Task t = new Task();
        t.Id = 1234;
        t.Title = "foo";
        t.StatusId = 5678;
    

    reference: http://blogs.msdn.com/b/adonet/archive/2009/11/06/foreign-key-relationships-in-the-entity-framework.aspx

    2
    8/18/2010 2:55:36 PM


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