Topics:

• Adapter Optimization
• DL/I Calls
• Record Selection Tests
• The Dynamic JOIN Command
• Retrieval of Unique Segments
• JOINs With Selection Criteria

This chapter explains how the adapter optimizes report generation. It includes the following topics:

• Adapter optimization (see Adapter Optimization).
• How the adapter constructs DL/I calls (see DL/I Calls).
• Record selection tests (see Record Selection Tests).
• Joins (see The Dynamic JOIN Command).
• Retrieval of unique segments (see Retrieval of Unique Segments).
• JOINs with selection criteria (see JOINs With Selection Criteria ).

Note:

• See your FOCUS documentation for information about retrieval of parent segments that lack descendant instances (short paths) and retrieval of segments from multiple paths in the hierarchy (multi-path requests).
• When you issue a request in a shared database environment, if an IMS call returns a GG status code (indicating an enqueue), the adapter attempts to retrieve the segment again. The request does not fail unless the adapter detects the GG status code ten times in succession.

This chapter includes sample report requests. Refer to Sample File Descriptions for complete file descriptions of the databases referenced in these examples.