ASA SQL User's Guide
  Working with Database Objects
    Working with tables

Managing foreign keys

This section describes how to create and edit foreign keys in your database. You can use either Sybase Central or Interactive SQL to perform these tasks.

Foreign keys are used to relate values in a child table (or foreign table) to those in a parent table (or primary table). A table may have multiple foreign keys that refer to multiple parent tables linking various types of information.

Managing foreign keys (Sybase Central)
Managing foreign keys (SQL)