Linq duplicate/copy the whole record

Question

I am using Linq to entities for general CRUD operations. Recently, i had a scenerio where i have to duplicate the whole record in the database (with different primary keys in all the related tables). My DB structure is pretty simple. I have a main table (lets say A) and other tables (lets say B, C, D). The main table holds the primary keys of table B,C,D as foreign keys.

I fetch a record from the database that i have to duplicate. Then i

1) change its object state to "Added" using context.objectStateManager.ChangeObjectState(AObj,EntityState.Added)

2) add the object in context using context.AddToA(AObj)

3) then i do saveChanges()

everything works fine on table A and properly new object is inserted.

If i do the same steps on Tables B,C,D i get an exception

1) change its object state to "Added" using context.objectStateManager.ChangeObjectState(AObj.B,EntityState.Added) //Here i access the child table B

2) add the object in context using context.AddToA(AObj)

3) then i do saveChanges()

The objectContext might be in an inconsistent state. A referential integrity constraint voilation occured. The property values that defines the refrential constraint are not consistent between principal and dependent objects in a relationship.

you might want to change the order in which you are saving so no key konstrains are created — COLD TOLD, Mar 31 '14 at 15:39
Well, i also tried to insert the data manually in the table(same as i was doing in the code) and everything got inserted with any error. Something is wrong with linq. — Behroz Sikander, Apr 01 '14 at 08:55
You don't need to Add the items, they are already in the context. You just need to change their state. — Honorable Chow, Apr 02 '14 at 15:00
ok guys, i managed to fix the issue. @COLDTOLD you are right i changed the order and things worked. — Behroz Sikander, Apr 03 '14 at 12:08
@HonorableChow thanks. I was doing the mistake that you mentioned. I just changed the state to Added and then no need to do AddObject. — Behroz Sikander, Apr 03 '14 at 12:08

score 0 · Answer 1 · edited May 23 '17 at 12:20

Read the object graph using AsNoTracking(), then it is just a matter of adding it and saving, no worries about order or state, I used this to implement a SaveAs feature in a recent project:

        var myGraph = tableA.Where(c => c.Id == id)
            .Include(c => c.childA)
            .Include(c => c.childB)
            .Include(c => c.childC)
            .AsNoTracking()
            .FirstOrDefault();

        if (myGraph != null)
        {
            myGraph.CopiedFromId = id;

            myGraph = Context.Set<TableA>().Add(myGraph);

            Context.SaveChanges();
        }

Here is a discussion on AsNoTracking()

Linq duplicate/copy the whole record

1 Answers1