Subschema Statements › LOGICAL RECORD Statement › Usage

Usage

Sequence of LR Elements in Program Storage Same as DDL Sequence

When a DML precompiler copies a logical-record description into a program's description of variable storage, each logical-record element is subordinate to the logical record itself. The sequence of logical-record elements in the copied description is the same as that in DDL LOGICAL RECORD statement. If a subschema record occurs more than once in a single logical record, the additional occurrences must be assigned unique IDs, called roles.

Must Modify Logical Record if Records Used in Logical Record Change

If any record used as a logical-record element is modified (through the schema compiler or the IDD DDDL compiler), the logical record must also be modified (through the subschema compiler) before the subschema load module is generated.

Must Use Role Names in PATH-GROUP Syntax

Once a role name has been assigned, that name must be used whenever PATH-GROUP syntax requires a logical-record element name.

Document All Logical Record Definitions

The following information should be included as COMMENTS for every logical record defined in the subschema:

• The DML verbs that a program using the subschema can issue in connection with logical-record-name
• The selection criteria that a program can include with each permitted logical-record DML verb
• The DBA-defined path statuses that can be returned for each permitted DML verb
• The sequence in which data is returned to the program