Chapter 2. SQL Remote Concepts
Publications and subscriptionsThedata that is replicated by SQL Remote is arranged in publications. Each
databasethat shares information in a publication must have a subscription
tothe publication.
Datais organized into
publications Thepublication is a database object describing data to be replicated.
Remoteusers of the database who wish to receive a publication do so by
subscribingto a publication.
Apublication may include data from several database tables. Eachtable’s
contributionto a publication is called an article. Eacharticle may consist of
awhole table, or a subset of the rows and columns in a table.
A two-table synchronization definition
Article 1: all of
table A
Article 2: some rows and
columns from table B
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Periodically,the changes made to each publication in a database are
replicatedto all subscribers to that publication. Thesereplications are called
publicationupdates.
Messagesare always
sentboth ways Remotedatabases subscribe to publications on the consolidated database so
thatthey can receive data from the consolidated database. Todo this, a
subscriptionis created at the consolidated database, identifying the
subscriberby name and by the publication they are to receive.
SQLRemote always involves messages being sent two ways. The
consolidateddatabase sends messages containing publication updates to
remotedatabases, and remote databases also send messages to the
consolidateddatabase.
Forexample, if data in a publication at a consolidated database is updated,
thoseupdates are sent to the remote databases. Andeven if the data is never
updatedat the remote database, confirmation messages must still be sent
backto the consolidated database, to keep track of the status of the
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