Robuta

https://www.ibm.com/docs/en/ims/15.2.0?topic=functions-creating-logical-relationships
Logical relationships resolve conflicts in the way application programs need to view segments in the database.
database administrationlogical relationshipsimscreating
https://www.ibm.com/docs/en/ims/15.3.0?topic=relationships-processing-segments-in-logical
Sometimes an application program needs to process a hierarchy that is made up of segments that already exist in two or more separate database hierarchies....
application programminglogical relationshipsimsprocessingsegments
https://www.ibm.com/docs/en/ims/15.2.0?topic=dbd-specifying-bidirectional-logical-relationships
When defining a bidirectional relationship with physical pairing, you need to include an LCHILD statement under both logical parents and, in addition to other...
database administrationlogical relationshipsimsspecifyingbidirectional