Delete rules

The following topics provide a description of how the delete values work for the logical parent, physical parent, and logical child.

Logical parent delete rules
The following list describes what happens when a logical parent is deleted when RULES=P, RULES=L, or RULES=V is specified.
Physical parent (virtual pairing only) delete rules
The following list describes the delete rules for a physical parent with virtual pairing only.
Logical child delete rules
The following list describes what happens when a logical child is deleted when RULES=P, RULES=L, or RULES=V is specified.
Examples using the delete rules
The following series of figures shows the use of the delete rules for each of the segment types for which the delete rule can be coded (logical and physical parents and their logical children).
Accessibility of deleted segments
Segments that are either physically deleted or logically deleted remains accessible under certain circumstances.
Possibility of abnormal termination
If a logical parent is physically and logically deleted, its DASD space is released. For this to occur, all of its logical children must be physically and logically deleted. However, the DASD space for these logical children cannot be released if the logical children have physical dependents with active logical relationships.
Avoiding abnormal termination
You must avoid creating a physically deleted logical child that can be accessed from below in the physical structure (using its third path). A logical child can be accessed from below if any of its physical dependents are accessible through logical paths.
Detecting physical delete rule violations
When a DLET call is issued, the delete routine scans the physical structure containing the segment to be deleted.
Treating the physical delete rule as logical
If the delete routine determines that neither the segment specified in the DLET call nor any physical dependent of that segment in the physical structure uses the physical delete rule, any physical rule encountered later (logical deletion propagated to logical child or logical parent causing physical deletion—V rule—in another database) is treated as a logical delete rule.
Inserting physically and logically deleted segments
When a segment is inserted, a replace operation is performed (space is reused), and existing dependents of the inserted segment remain if certain conditions are met.
Delete rules summary
The following list provides a summary of the delete rules.

Parent topic: Insert, delete, and replace rules for logical relationships