Adding referential constraints

You can add referential constraints on physical files with no more than one member. A referential constraint is a file-level attribute; therefore, you can create the constraint before the member exists.

• Before you add referential constraints
  Before you add referential constraints, make sure that you meet these prerequisites.

• Defining the parent file in a referential constraint
  A parent file must be a physical file with a maximum of one member. You can either create a parent file or use an existing file as the parent file.

• Defining the dependent file in a referential constraint
  A dependent file must be a physical file with a maximum of one member. You can either create a dependent file as you do any physical file or use an existing file as the dependent file.

• Specifying referential constraint rules
  Referential constraints allow you to specify the rules that you want the system to enforce when you delete or update records.

• Details: Adding referential constraints
  Consider these limitations when adding referential constraints.

• Details: Avoiding constraint cycles
  A constraint cycle is a sequence of constraint relationships in which a descendent of a parent file becomes a parent to the original parent file. You can use constraint cycles in a DB2 Universal Database™ for iSeries™ database; however, you should avoid using them.

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