inters all over the
database makes it very hard to reorganize the database. In effect, once
you store a pointer to a record, it is difficult to move that record
elsewhere.  Some network databases handle this by leaving forwarding
pointers behind, but this defeats the speed advantage of doing a single
disk access in the first place. Other network databases find, and fix,
all the pointers to a record when it moves, but this makes
reorganization very expensive. Reorganization is often necessary in
databases, s