An error occurred while saving entities that do not expose foreign key properties for their relationships

Question

I have a simply code in Entity Framework 4.1 code first:

PasmISOContext db = new PasmISOContext();
var user = new User();
user.CreationDate = Da         


        

Answer 1

In my case the exeception was thrown because EF had created a migration incorrectly. It missed setting the identity: true on the second table. So go into the migrations which created the relevant tables and check if it missed to add identity.

CreateTable(
    "dbo.LogEmailAddressStats",
    c => new
        {
            Id = c.Int(nullable: false, identity: true),
            EmailAddress = c.String(),
        })
    .PrimaryKey(t => t.Id);

CreateTable(
    "dbo.LogEmailAddressStatsFails",
    c => new
        {
            Id = c.Int(nullable: false), // EF missed to set identity: true!!
            Timestamp = c.DateTime(nullable: false),
        })
    .PrimaryKey(t => t.Id)
    .ForeignKey("dbo.LogEmailAddressStats", t => t.Id)
    .Index(t => t.Id);

An Id column should have identity (i.e. auto-incrementing!) so this must be a EF bug.

You could add identity manually with SQL directly to the database but I prefer using Entity Framework.

If you run in to the same problem I see two easy solutions:

Alt 1

reverse the incorrectly created migration with

update-database -target:{insert the name of the previous migration}

Then add the identity: true manually to the migration code and then update-database again.

Alt 2

you create a new migration that adds identity. If you have no changes in the models and you run

add-migration identity_fix

it will create an empty migration. Then just add this

    public partial class identity_fix : DbMigration
    {
        public override void Up()
        {
            AlterColumn("dbo.LogEmailAddressStatsFails", "Id", c => c.Int(nullable: false, identity: true));
        }

        public override void Down()
        {
            AlterColumn("dbo.LogEmailAddressStatsFails", "Id", c => c.Int(nullable: false));
        }
    }