For a customer I needed to do a review there database (MSSQL 2000 database). For this I wanted to create some database diagrams. When I tried to create a diagram with Sql Sever Management Studio I got the following message:
"Database diagram support objects cannot be installed because this database does not gave a valid owner."
To fix this problem you need to set the owner and change the Compatibility Level of the database. You can do this with the following steps within Sql Sever Management Studio:
1. Right Click on your database, choose properties
2. Goto the Options Page
3. In the Dropdown at right labeled "Compatibility Level" choose "SQL Server 2005(90)"
4. Goto the Files Page
5. Enter "sa" in the owner textbox, or any other user you want to be the owner.
6. Click the OK button