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Summary

Transforming data and contents of the LCR during the replication process is a very powerful and flexible feature of Oracle Streams. Sometimes such transformations are required to fulfill business and statutory requirements. These transformations can be performed during the capture, propagation, or apply process, depending on the requirements of the destination applications. The transformations are attached to a particular rule and are triggered only when the rule evaluates to TRUE.

Oracle-provided procedures address most commonly used transformations. These declarative rule-based transformations are recommended when possible. You can also write PL/SQL functions for custom rule-based transformations for actions not handled by declarative transformations. Since the declarative rule-based transformations do not use PL/SQL procedures, they run much more efficiently than the corresponding custom rule-based transformations. Custom rule-based transformations may be required when replicating DDL changes in addition to the DML changes. When there are multiple transformations defined for the same rule, Oracle executes those in a particular order. The execution order can be changed if required. Be aware that the result of one transformation becomes the input to the next transformation.


  

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