Automatically updated cross reference system having increased flexibility

摘要

A method of maintaining cross reference information regarding a user program comprises the steps of determining that an aspect of a first referencee has been modified, notifying a first referencer that the aspect of the first referencee has been modified, and updating cross reference information. The notifying step is performed by the first referencee, and the updating step is performed by the first referencer. The cross reference information is stored in a database comprising an entry for each reference made by a referencer to a referencee. Each entry stores a unique identifiers which identify a respective referencer and referencee. The cross reference information is automatically updated through a notification procedure in which referencees are responsible for notifying referencers when an aspect of the referencee changes, and the referencers are thereafter responsible for updating the cross reference information. The present invention provides increased flexibility in terms of the types of cross reference information which is maintained and the types of actions which a user is allowed to take without losing cross reference information. For example, the cross reference system is able to manage references to a referencee before the referencee is created and after the referencee is deleted.