PowerExchange captures change data from DB2 recovery log files for the database that contains your source tables. For CDC to work, archive logging must be active for the database. Also, you must create a PowerExchange capture catalog table in the source database. The capture catalog table stores information about the source tables and columns, including DB2 log positioning information.

If you have a source table with user-defined fields or multi-field columns, you can create a data map to manipulate these fields with expressions. For example, you might want to create data map to manipulate packed data in a CHAR column. If you create a data map, you must still create a capture registration and merge the data map with the extraction map that is generated for the capture registration.