The following are advantages of defining multiple tables in a single Master File:

• For reporting, a multi-table structure automatically joins tables referenced in the report request, so relationships between tables can be pre-defined for a user without creating an additional RDBMS view.
• A multi-table structure creates a logical view of the data tailored to contain only those columns that should be seen by a user. The DBA security feature can define additional levels of security.
• Tables described in a multi-table Master File can be maintained together using the FOCUS MODIFY and Maintain facilities and can take advantage of FOCUS referential integrity provided by the adapter. (Refer to Maintaining Tables With FOCUS for a description of MODIFY, Maintain, and FOCUS referential integrity.)
• TABLE requests access only those RDBMS tables that contain columns referenced (either explicitly or implicitly) in the request.

  A TABLE request that references a dynamically joined structure generates SQL join predicates for all segments in the subtree that starts from the root segment. Multi-table Master Files do not necessarily generate these predicates. In a multi-table structure, the subtree effectively begins with the highest referenced segment. This difference may cause identical TABLE requests to produce different reports when run against a dynamic join structure and a multi-table Master File that represent the same tree structure. See Advanced Reporting Techniques for a discussion of dynamic joins.