Restore nulled child links as well as a deleted parent

When a PostgreSQL parent deletion mixes ON DELETE CASCADE and ON DELETE SET NULL, recreating the parent—even with its original ID—does not restore the aggregate. Cascaded membership or routing rows are gone, while surviving child rows have lost their parent association. Recover the pre-deletion relationship set from a backup or trustworthy history, then reconcile it with current state before proposing a selective repair. A matching parent name is insufficient evidence for reassignment. This applies only where those foreign-key actions are actually deployed; historical configuration and backup availability still require verification.

Applies when: recovering a deleted group whose memberships disappear but business records survive without their group link. Keywords: PostgreSQL foreign key cascade set null recovery backup membership routing