For self-describing trails, if an explicit column mapping does not exist, either by using COLMATCH or COLMAP, Oracle GoldenGate maps source and target columns by default according to the following rules.

This doesn't apply if you are using SOURCEDEFS or TARGETDEFS.

• If a source column is found whose name and case exactly match those of the target column, the two are mapped.

• If no case match is found, fallback name mapping is used. Fallback mapping performs a case-insensitive target table mapping to find a name match. Inexact column name matching is applied using upper cased names. This behavior is controlled by the GLOBALS parameter NAMEMATCHIGNORECASE. You can disable fallback name matching with the NAMEMATCHEXACT parameter, or you can keep it enabled but with a warning message by using the NAMEMATCHNOWARNING parameter.

• Target columns that do not correspond to any source column take default values determined by the database.

If the default mapping cannot be performed, the target column defaults to one of the values shown in the following table.