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Data Replication with SQL Remote

Part 1 Introduction to SQL Remote

Chapter 2: SQL Remote Replication Concepts

SQL Remote components

SQL Remote components

The following components are required for SQL Remote:

• Data server

  An Adaptive Server Anywhere or Adaptive Server Enterprise database management system is required at each site to maintain the data.

• Message Agent

  A SQL Remote Message Agent is required at the consolidated site and at each remote site to send and receive SQL Remote messages.

  The Message Agent connects to the data server by a client/server connection. It may run on the same machine as the data server or on a different machine.

• Database extraction utility

  The extraction utility is used to prepare remote databases from a consolidated database, during development and testing, and also at deployment time.

• Message system client software

  SQL Remote uses existing message systems to transport replication messages. A file-sharing "message system" is provided, which does not require client software. Each computer involved in SQL Remote replication using a message system other than file sharing must have that message system installed.

• Client applications

  The applications that work with SQL Remote databases are standard client/server database applications.

The data server

The data server may be an Adaptive Server Enterprise or an Adaptive Server Anywhere server. At the remote site the data server is commonly an Adaptive Server Anywhere personal server, but can also be an Adaptive Server Enterprise or Adaptive Server Anywhere server.

Client applications

Client applications work with the data in the database. Client applications use one of the client/server interfaces supported by the data server:

• For Adaptive Server Anywhere, the client application may use ODBC, Embedded SQL, or Sybase Open Client to work with Adaptive Server Anywhere.

• For Adaptive Server Enterprise, the client application may use one of the Sybase Client Server interfaces, ODBC, or Embedded SQL.

Client applications do not have to know if they are using a consolidated or remote database. From the client application perspective, there is no difference.

The Message Agent

The SQL Remote Message Agent sends and receives replication messages. It is a client application that sends and receives messages from database to database. The Message Agent must be installed at both the consolidated and at the remote sites.

For Adaptive Server Anywhere, the Message Agent is a program called dbremote.exe on PC operating systems, and dbremote on UNIX.

For Adaptive Server Enterprise, the Message Agent is a program called ssremote.exe on PC operating systems, and ssremote on UNIX.

Message system client

If you are using a shared file message system, no message system client is needed.

If you are using an e-mail or other message system, you must have a message system for that client in order to send and receive messages.