replication.
Bothdatabases
subscribe Messages must be sent both ways, so not only does a remote database
subscribeto a publication created at the consolidated database, but the
consolidateddatabase must subscribe to a corresponding publication created
atthe remote database.
Consolidated
database
Remote
database
Publish SubscribePublishSubscribe
Data updates and
receipt confirmations
Data updates and
receipt confirmations
Whenremote database users modify their own copies of the data, their
changesare replicated to the consolidated database. Whenthe messages
containingthe changes are applied at the consolidated database the changes
becomepart of the consolidated database’s publication, and are included in
thenext round of updates to all remote sites (except the one it came from).
Inthis way, replication from remote site to remote site takes place via the
consolidateddatabase.
Synchronizinga remote
database Whena subscription is initially set up, the two databases must be brought to
astate where they both have the same set of information, ready to start
replication. This process of setting up a remote database to be consistent
withthe consolidated database is called synchronization. Synchronization
canbe carried out manually, but the database extraction utility automates the
process. Youcan run the Extraction utility as a command-line utility or, if
youare using an Adaptive Server Anywhere consolidated database, from
SybaseCentral.
Theappropriate publication and subscription are created automatically at
remotedatabases when you use the SQL Remote database extraction utility
tocreate a remote database.
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