Database Diagram Support Objects cannot be Installed … no valid owner

Question

I tried to create a database diagramm with SQL Server 2008, but an error occurs:

Database diagram support objects cannot be installed because this dat

Answer 1

The real problem is that the default owner(dbo) doesn't have a login mapped to it at all.As I tried to map the sa login to the database owner I received another error stating "User,group, or role 'dbo' already exists...".However if you try this code it will actually works :

EXEC sp_dbcmptlevel 'yourDB', '90';

go

ALTER AUTHORIZATION ON DATABASE::yourDB TO "yourLogin"

go

use [yourDB]

go

EXECUTE AS USER = N'dbo' REVERT

go