Here I asked what are permissions to read database diagrams:
SQL Server: permissions to read database diagrams
Suggested answer is "db_owner" role... But in this case user will OWN DB.
Is it possible to provide read-only access to DB without granting any kind of 'update/modify' rights?
If you are asking whether a user can be the owner of a database and yet not be able to modify the data contained in any way (i.e. insert, update, delete), the answer is no. The closest you could get it to flag the entire database as read-only, and even then the owner could always change it back to read/write.