CA-IDMS Data Adapter Reporting Techniques

This chapter explains how your Master File is used to select segments and retrieve data from them. It also discusses:

• How screening conditions (IF criteria) improve I/O efficiency (see Effects of Screening Conditions on Retrieval).
• Unique and non-unique segments with short paths (see Retrieving Short Paths).
• How you can change retrieval logic by specifying a new root segment (see File Inversion).
• How you can join structures together for reporting purposes (see The JOIN Command).

The examples in this chapter reference the EMPFULL Master and Access Files. Creating File Descriptions With AUTOIDMS, contains a sample session that demonstrates how to create the EMPFULL Master and Access Files. For a complete listing of these file descriptions, see CA-IDMS Data Adapter Samples.

Note:

The term record refers to a record occurrence; it should not be confused with the IDMS term record-type.

Topics pertaining to unique segments discuss considerations/implications that are true regardless of whether the unique segment is an owner of its parent or related to it through a CALC field, index, or LRF field.

• The Retrieval Subtree
• Retrieval Sequence
• Effects of Screening Conditions on Retrieval
• Retrieving Short Paths
• File Inversion
• The JOIN Command