Microsoft® SQL Server™ 2008 All-In-One Desk Reference For Dummies®

VIII.5.1. Exploring the Publishing Metaphor

Replication is based on a publishing metaphor. In the publishing world, there are publishers, distributors, and subscribers. Replication defines different roles based on the real-world example of publishing.

• Publishers: Publishers maintain the source database that will be replicated.

• Distributors: Distributors send the desired portions of the database to subscribers. Often, the publisher also fulfills the role as a distributor, but this isn't required. When a large number of subscribers exist, distributors take some of the load off the publisher.

• Subscribers: Subscribers receive the replicated data in the form of a publication.

  Figure 5-1 shows the relationship between publishers, distributors, and subscribers. Remember though, it's very common for the publisher to also fulfill the distributor role.

  The data that is published and distributed isn't necessarily the entire database. Instead, portions of the database (such as tables and indexes) are identified to be published. The published data are referred to as articles and publications:

• Articles: Articles are the individual database objects that are published. These objects are typically tables, indexes, and stored procedures, but can be any object within the database.

• Publication: A publication includes one or more articles. Subscribers can subscribe to publications (but not individual articles).

  Figure VIII.5-1. Replication among the publisher, distributor, and subscribers.

  This works similarly ...