The term heterogeneous replication refers to replicating data-changing operations between two databases of different vendors. For example:
A replication system in which Adaptive Server Enterprise (ASE) is either the primary or the replicate data server, and a non-ASE data server (such as IBM DB2 UDB) is the other data server.
A replication system in which the primary and replicate data servers are both non-ASE data servers (for example, Oracle is the primary data server and IBM DB2 UDB is the replicate data server, or Microsoft SQL Server is the primary server and Microsoft SQL Server is the replicate server).
Adaptive Server Enterprise was enhanced to support Replication Server. 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 provided are required to implement a Sybase replication system with non-ASE data servers:
A Replication Agent
Enterprise Connect Data Access (ECDA) or a data server whose connectivity requirements are compatible with Replication Server
Figure 1-2 illustrates a typical Sybase replication system with non-ASE data servers, showing the flow of data between the data servers, through the Replication Agent, Replication Server, and Enterprise Connect Data Access database gateway.
Figure 1-2: Sybase replication system with non-ASE data servers
Replication Agents support non-ASE data servers by reading the completed transactions in the primary database and sending them to Replication Server for distribution.
ECDA database gateways support IBM DB2 UDB, Microsoft SQL Server, and Oracle data servers by providing connectivity between Sybase Open Client and Open Server and either ODBC or the native protocol of the replicate data server, and by providing SQL transformation and other services. Replication Server also includes datatype support for non-ASE data servers.
