An on-line reorganization method of an object-oriented database with physical references involves a novel fuzzy traversal of the database, or a partition thereof, to identify the approximate parents of all migrating objects. Where the entire database is traversed the process begins from its persistent root. For traversals of a partition the process begins from each object with a reference pointing to it from outside the partition. To facilitate the identification of these inter-partitional objects an External Reference Table (“ERT”) is maintained. During the fuzzy traversal all new inserted and deleted references are tracked in a Temporary Reference Table (“TRT”). After the fuzzy traversal is completed, for each migrating object, a lock is obtained on the identified approximate parents and on all new parents in which references to the object were inserted, as indicated by the TRT. Based on the information in the TRT, locks are released on all approximate parents whose references to the object have been deleted. The references to the migrating object in the remaining set of locked parents are updated, the object is relocated and the locks are released. Alternatively, each parent of a migrating object can be individually locked, updated and released.