Add 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 can add referential constraints, you must make sure that you meet some conditions.
• Define the parent file in a referential constraint
  A parent file must be a physical file with a maximum of one member. You can create a new file or use an existing file when you define the parent file.
• Define the dependent file in a referential constraint
  A dependent file must be a physical file with a maximum of one member. You can create a dependent file as you do any physical file or use an existing file.
• Specify referential constraint rules
  Referential constraints allow you to specify rules that you want the system to enforce when you delete or update records.
• Details: Add referential constraints
  Here is a list of limitations that apply to referential constraints.
• Details: Avoid 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.