The term heterogeneous replication refers to replicating data-changing operations between heterogeneous data servers (that is, data servers that are supplied by different vendors). For example:
A replication system in which Adaptive Server Enterprise is either the primary or the replicate data server, and a non-Sybase data server (such as DB2 Universal Database) is the other data server
A replication system in which the primary and replicate data servers are different non-Sybase data servers (for example, Oracle is the primary data server and DB2 Universal Database is the replicate data server)
This book also addresses Sybase replication systems
with no Adaptive Server, and just one type of non-Sybase data server
(for example, a system in which both the primary and replicate data
servers are Oracle). This is not a heterogeneous replication system,
because only one type of data server is used, but the issues you
must consider are the same as heterogeneous replication issues.
Adaptive Server Enterprise is the data server that Sybase Replication Server was designed to work with. All of the data server elements required to support Replication Server (that is, a data-change capture mechanism in the primary database, and system tables and stored procedures in the replicate database) are either built into Adaptive Server Enterprise, or enabled by utilities that are provided with the Replication Server or Adaptive Server software.
Two additional components are required to implement a Sybase replication system with non-Sybase data servers:
A Replication Agent™
A database gateway (such as Sybase DirectConnect™)
Figure 1-2 illustrates a Sybase replication system with non-Sybase data servers, showing the flow of data between the data servers, through the Replication Agent, Replication Server, and DirectConnect database gateway.
Figure 1-2: Sybase replication system with non-Sybase data servers
Replication Agents support non-Sybase data servers by capturing the data-changing operations in the primary database, and sending them to Replication Server for distribution.
DirectConnect database gateways support non-Sybase data servers by providing connectivity between Sybase Open Client/Server and either ODBC, or the native protocol of the data server, and by providing SQL transformation and other services.
Replication Server also includes features and utilities that support non-Sybase data servers. See “Replication Server heterogeneous datatype support” for more details about Replication Server support for non-Sybase data servers.
