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.

The following figure and code show an example of treating the physical delete rule as logical.

Figure 1. Example of treating the physical delete rule as logical

GHU 'SEG8'  STATUS='  '
DLET        STATUS='  '

SEG8 and SEG9 are both physically deleted, and SEG9 is logically deleted (V rule). SEG5 is physically and logically deleted because it is the physical pair to SEG9 (with physical pairing setting the LD bit in one set, the PID bit in the other, and vice versa). Physically deleting SEG5 causes propagation of the physical delete to SEG5's physical dependents; therefore, SEG6 and SEG7 are physically deleted.

Note that the physical deletion of SEG7 is prevented if the physical deletion started by issuing a DLET call for SEG4. But the physical rule of SEG7 is treated as logical in this case.