Setting access control : System Architect Catalog Manager : What is an enterprise catalog?
  
What is an enterprise catalog?
An enterprise catalog is a SQL Server database that controls user access to other databases on the same server: those other databases are System Architect Enterprise type encyclopedias. Access control is enforced only on encyclopedias you attach to a catalog. The catalog manages the permissions by assigning to users, roles that determine the diagrams and definitions they can work on, and the System Architect menus and macros they can run against encyclopedias.
System Architect Catalog Manager (SACM) controls access to shared encyclopedias by forming multiple three-way relationships between users, encyclopedias, and roles. Permissions are assigned to roles. Users are assigned to encyclopedias, and are assigned one or more roles on those encyclopedias, for each encyclopedia in the catalog. From a user’s point of view, you are assigned an encyclopedia, and are given a role to play on the encyclopedia.
Other items of note regarding catalogs:
One catalog can control access to multiple encyclopedias on the same server.
You can only attach an encyclopedia to one catalog at a time.
Cataloged encyclopedias are identified as the type enterprise; non-cataloged as professional.
When professional encyclopedias are attached to their corresponding catalogs, they become enterprise encyclopedias, and must be reopened for access control to take effect.
SACM controls permissions to the catalog database, enabling you to assign the Administrator role to other users. This lets you delegate some or all catalog-related tasks to others. The SACM installer has ultimate control over catalogs and by extension, to all the encyclopedias you attach to them.
See also
System Architect Catalog Manager