In this first installment of a 2-part series, Mahesh describes and explains what Replication is, its features and benefits, and how you can put it to use.
Replication: SQL Server 2000 - Part 1 - Implementing Replication (Page 6 of 7 )
With the above basic knowledge we can now proceed to understand the implementation of replication. There are different ways by which you can implement and monitor replication based on different replication types. But in general replication has the following general steps:
Configuring replication
Generating and applying initial snapshot
Modifying replicated data
Synchronizing and propagating data
Configuring Replication:
Configuring replication involves the following steps:
Configure the publisher and distributor. Distributor can be on the same server or even on a different server
Create publications based on data, sub sets of data and database objects
Determine the type of replication to use, the subscriber database and location of the snapshot file
Configure when the synchronization will occur and options that will be used with publications
Create push and/or pull subscriptions at either the publisher or the subscriber and configure your replication schedule and options
Generating and Applying Initial Snapshot:
SQL server 2000 creates a snapshot of data and schema and saves it in the snapshot file location. After the subscription is created, the snapshot is applied, and is based on a configured schedule. Creating a publication or a snapshot can be applied manually. The snapshot agent is responsible for creating the snapshot file and stores it in the snapshot file location.
Modifying Replicated Data:
Depending on the type of replication and replication options, the subscriber will be able to modify the data after the snapshot has been applied and propagate the changes back to the publisher or other subscribers.
Synchronizing and Propagating Data Changes:
Synchronization refers to the propagation of data changes between subscriber and publisher. How the data is synchronized is dependent on the type of replication used.
Incase of snapshot replication, a snapshot file is reapplied at the subscriber
Incase of transactional replication, all data modification through Insert/Update and Delete are distributed between publisher and subscriber
Incase of merge replication, data modification at various servers are merged. Conflicts, if any, are detected and resolved.