Self-describing trail files are the default if the trail file format is 12.2 or higher, if you are not using SOURCEDEFS OVERRIDE or TARGETDEFS OVERRIDE. Oracle recommends that you use self-describing trail files. You should only use SOURCEDEFS OVERRIDE and TARGETDEFS OVERRIDE for backward compatibility requirements.

The following are the guidelines for using self-describing trails:

• If using the self-describing trails, then the column names on the source are mapped to the column names in the target table. Order of columns doesn't matter and if column names are different, then they need to be explicitly mapped using COLMAP.

• If the source Oracle GoldenGate release is 12.1 or earlier, then you need to use SOURCEDEFS OVERRIDE or TARGETDEFS OVERRIDE. See SOURCEDEFS OVERRIDE and TARGETDEFS OVERRIDE in the Reference for Oracle GoldenGate.