Updating the catalog will update all catalog records and remove invalid records. It does this by deleting all indexes and re-cataloging all currently indexed objects.

Clearing the catalog will remove all entries and create new tables if necessary.

Clearing reserved uids allows for reducing the size of the catalog after many Zope restart. It can be a dangerous operation if deferred execution of cataloging of objects has not been completed.

Exporting properties produces a human-readable XML file which can be imported later. It is useful to reconstruct the same catalog information.