Copyright 2002 by
Prentice Hall, Inc.
7-22
Alternatives to “True” Distributed Databases
nDownloaded data files: e.g.,
sending data from mainframes to
PCs, most popular method for
distributing data
nCopies of data stored at nodes: helps process customer activity during the day, night official updating of the master files
nNot fully synchronized
DB: second copies in cache, errors cause a new primary copy