Oracle Distributed Systems

Table Replication

Certainly the most versatile and intriguing component of Oracle’s advanced replication facility is multi-master table replication. Any replicated table can be updated anywhere, and the changes will appear in all participating master sites. However, as with any sophisticated technology, you must configure multi-master replication with great care in order to avoid perils and pitfalls.

This section describes the API calls used to create and to maintain replicated tables, points out techniques to make the administration job easier, and describes some practices that will help you to avoid trouble.

API Calls

The fundamental DBMS_REPCAT procedures for administering replicated tables are as follows:

DBMS_REPCAT. ADD_UNIQUE_RESOLUTION

Adds a uniqueness conflict resolution handler to the table.

DBMS_REPCAT .ADD_UPDATE_RESOLUTION

Adds an update conflict resolution handler to the table.

DBMS_REPCAT. DEFINE_COLUMN_GROUP

Creates an empty column group.

DBMS_REPCAT. DROP_COLUMN_GROUP

Drops a column group.

DBMS_REPCAT. DROP_UNIQUE_RESOLUTION

Drops a uniqueness conflict handler.

DBMS_REPCAT. DROP_UPDATE_RESOLUTION

Drops an update conflict handler.

DBMS_REPCAT. MAKE_COLUMN_GROUP

Creates a column group and assigns columns to the group.

DBMS_REPCAT. SEND_AND_COMPARE_OLD_VALUES

Specifies which columns should send their previous values to remote sites for comparison during updates and deletes.

DBMS_REPCAT. SET_COLUMNS

Specifies the column(s) to use to uniquely identify records in the table.