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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.


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