Чтобы использовать Database Diagram Designer, он должен быть сначала настроен членом роли db_owner (роль баз данных SQL Server) для управления доступом к диаграммам.
Некоторые моменты, которые следует учитывать при владении диаграммой:
• Although any user with access to a database can create a diagram, once the diagram has been created, the only users who can see it are the diagram's creator and any member of the db_owner role.
• Ownership of diagrams can only be transferred to members of the db_owner role. This is only possible 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 will remain 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 over ownership of the diagram.
Пожалуйста, обратитесь к аналогичной теме, Аарон дал два обходных пути:
1. In a Logon trigger, update the principal_id of all diagrams to be the current login. This means they will have access to all diagrams until the next person logs in.
2. Use a trigger on the sysdiagrams table itself, and whenever a diagram is created or updated, add / update a copy for each principal (with their user name appended).
Ссылка на тему: https://dba.stackexchange.com/questions/43946/permission-required-to-view-a-database-diagram