Method and apparatus for tracking data in a database, employing last-known location registers

In accordance with the present invention, a data tracking scheme for a database is provided which employs a "last-known location" register as a part of a data block's ID. In certain object-oriented databases embodying the present invention, for example, when an object is created, it is assigned a physical address, which is then included as an extension of the OID, and which is recorded in a logical address register. When the object is moved, rather than identifying every reference to the object within the database, only the physical address in the logical address register is updated. When a reference to the object is encountered during the operation of the database, the last-known-location extension of the OID is consulted for a valid last-known location, that is, a valid physical address. If such a valid last-known location exists, that physical location is accessed in order to retrieve the object. If the last-known-location extension of the OID contains an invalid last-known location, or if the physical address indicated contains something other than the desired object, the logical address register is accessed and the correct physical address is found. At this point, the reference to the object may (but need not) update the last-known address extension of the OID of the target object.