Understanding Database Diagram Ownership
To use Database Diagram Designer, a member of the db_owner role (a role of Microsoft SQL Server databases) must first set up the designer to control access to diagrams. Each diagram has only one owner: the user who created it. For more information about how to set up diagramming, see How to: Set Up Database Diagram Designer.
You should keep the following points about diagram ownership in mind:
Any user who has access to a database can create a diagram. After a user creates a diagram, only that user and any member of the db_owner role can see the diagram.
Ownership of diagrams can be transferred only to members of the db_owner role. This transfer is possible only if the previous owner of the diagram has been removed from the database.
If the owner of a diagram has been removed from the database, the diagram remains in the database until a member of the db_owner role attempts to open it. At that point, the db_owner member can choose to take ownership of the diagram.
See Also
Tasks
How to: Set Up Database Diagram Designer