Application Development Guide

Managing Referential Integrity

Different systems handle referential constraints differently:

DB2 Universal Database for OS/390

An index must be created on a primary key before a foreign key can be created using the primary key. Tables can reference themselves.

DB2 for VSE & VM

An index is automatically created for a foreign key. Tables cannot reference themselves.

DB2 Universal Database for AS/400

An index is automatically created for a foreign key. Tables can reference themselves.

DB2 Universal Database

For DB2 Universal Database databases, an index is automatically created for a unique constraint, including a primary key. Tables can reference themselves.

Other rules vary concerning levels of cascade.