Question

Sorry if the title is poorly descriptive, but I can’t do better right now =(

So, I have this master-detail scheme, with the detail being a tree structure (one to many self relation) with n levels (on SQLServer 2005)

I need to copy a detail structure from one master to the another using a stored procedure, by passing the source master id and the target master id as parameters (the target is new, so it doesn’t has details).

I’m having troubles, and asking for your kind help in finding a way to keep track of parent id’s and inserting the children without using cursors or nasty things like that…

This is a sample model, of course, and what I’m trying to do is to copy the detail structure from one master to other. In fact, I’m creating a new master using an existing one as template.

Answer 1

If I understand the problem, this might be what you want:

INSERT dbo.Master VALUES (@NewMaster_ID, @NewDescription)  INSERT dbo.Detail (parent_id, master_id, [name]) SELECT detail_ID, @NewMaster_ID, [name] FROM dbo.Detail  WHERE master_id = @OldMaster_ID  UPDATE NewChild SET parent_id = NewParent.detail_id FROM dbo.Detail NewChild JOIN dbo.Detail OldChild ON NewChild.parent_id = OldChild.detail_id JOIN dbo.Detail NewParent ON NewParent.parent_id = OldChild.parent_ID WHERE NewChild.master_id = @NewMaster_ID AND   NewParent.master_id = @NewMaster_ID AND   OldChild.master_id = @OldMaster_ID 

The trick is to use the old detail_id as the new parent_id in the initial insert. Then join back to the old set of rows using this relationship, and update the new parent_id values.

I assumed that detail_id is an IDENTITY value. If you assign them yourself, you’ll need to provide details, but there’s a similar solution.