Accessing LCR Contents

The rules in Oracle Streams, and sometimes the custom procedures such as DML handlers, DDL handlers, and error handlers, access the contents in the LCR. Access to this information is required while evaluating a rule. Accessing the column names and their values is required when you want to track data changes, transform the data, audit certain commands, or filter out certain DML or DDL operations. Oracle Streams provides required APIs to achieve all of these tasks.

As you learned earlier, the Oracle Streams queues are of ANYDATA data type, which is an Oracle-supplied object type. The ANYDATA type can hold instances of any other Oracle data types, such as NUMBER, DATE, CLOB, and VARCHAR2, including other Oracle-supplied object types.