Because data warehousing applications are more iterative than OLTP systems, the database structures and schemas can change more often. Visual database diagrams provide physical data modeling tools for SQL Server database administrators, which can simplify the definition and change cycles.
The visual database diagrams are stored on the database server using SQL Server Enterprise Manager. Changes to either the database or the diagrams are reflected in the other.
A wizard is available that automates the selection and layout of tables in an existing database. However, database entities (tables and their relationships) can be defined entirely within the diagram tool. The visual database diagram shows tables and their relationships, and allows changes to the structure of individual tables and to the constraints linking the tables.