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

Chapter VIII.5. Replication

Very often, you need to have all or some of your data in more than one place at the same time. If the data is never modified, you could just make a copy of it as you would make a copy of a piece of paper on a Xerox copier. However, databases are rarely static. They change. Although it's impossible to update the copied piece of paper when the original changes (at least it's impossible today), replicating the changes from one database to another database is possible.

The goal of replication is to make copies of the data and ensure those copies are kept up to date. How often the data is updated depends on how often the data changes and how up to date the data needs to be. Some of the reasons to replicate data are to offload the reporting workload to another SQL Server, replicate the data to dedicated backup server so backups can occur without interfering with the online server, and keeping data centralized from several branch office databases.