Entity Framework InvalidOperationException on Save

Question

When I create a new EF object, I first attach it to the DbSet then set one of its Navigation Properties to a new instance of a different EF object. I then add the first EF to the DbSet and call save. I get the following exception:

System.InvalidOperationException: The changes to the database were committed 
successfully, but an error occurred while updating the object context. The 
ObjectContext might be in an inconsistent state. Inner exception message: A 
referential integrity constraint violation occurred: The property value(s) of 
'Location.Id' on one end of a relationship do not match the property value(s) 
of 'Pool.LocationId' on the other end.

Here's my code:

ORMContext context = new ORMContext();

var l = context.Locations.Create();
context.Locations.Attach(l);
...set properties
context.Locations.Add(l);

var p = context.Pools.Create();
context.Pools.Attach(p);
p.Location = l;
...set properties
context.Pools.Add(p);

context.SaveChanges();

What I think is happening is the Location object is new and its Id is 0 by default. EF is updating the foreign key on Pool (which is set to 0 ) and then Location.Id gets updated after the Location object is saved to the database. So Location.Id is now set to the associated value in the database, say 149 , and Pool.LocationId is still set to 0 .

How do I avoid this exception? Or how am I suppose to handle it?

Answer 1

You can save after adding the location, that way the reference to the entity will be set

    ORMContext context = new ORMContext();

    var l = context.Locations.Create();
    context.Locations.Attach(l);
    ...set properties
    context.Locations.Add(l);

    context.SaveChanges(); // save here, that way the location will get its Id
    var p = context.Pools.Create();
    context.Pools.Attach(p);
    p.Location = l;
    ...set properties
    context.Pools.Add(p);

    context.SaveChanges();

That would be a way