Working in a Multi-User Environment

You can work with database diagrams in a multi-user environment; that is, an environment in which more than one user may make changes to a database diagram and the database at a time. When you save a diagram, the Database Designer verifies that the database has not been modified since you last saved the diagram. If another user has made changes, you will be notified that the database has been modified. You may need to reconcile these changes, both in the database diagram and in the database itself.

To See
Work with others on shared database diagrams Multi-User Environments
Resolve changes made to a database diagram by multiple users Reconciling a Database Diagram with a Modified Database