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Chapter 2. SQL Remote Concepts
Publications and subscriptions
The data that is replicated by SQL Remote is arranged in publications. Each
database that shares information in a publication must have a subscription
to the publication.
Data is organized into
publications
The publication is a database object describing data to be replicated.
Remote users of the database who wish to receive a publication do so by
subscribing to a publication.
A publication may include data from several database tables. Each table’s
contribution to a publication is called an article. Each article may consist of
a whole 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
replicated to all subscribers to that publication. These replications are called
publication updates.
Messages are always
sent both ways
Remote databases subscribe to publications on the consolidated database so
that they can receive data from the consolidated database. To do this, a
subscription is created at the consolidated database, identifying the
subscriber by name and by the publication they are to receive.
SQL Remote always involves messages being sent two ways. The
consolidated database sends messages containing publication updates to
remote databases, and remote databases also send messages to the
consolidated database.
For example, if data in a publication at a consolidated database is updated,
those updates are sent to the remote databases. And even if the data is never
updated at the remote database, confirmation messages must still be sent
back to the consolidated database, to keep track of the status of the
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