To declare mapping on a target column, does a developer have to manually write the required database functions?

To declare mapping on a target column, does a developer have to manually write the
required database functions?

A.
Yes, ODI only allows manual insertion of information related to source-target mappings.

B.
Yes, either the work area can be used to write the functions or a configuration file can be
prepared for ODI to read.

C.
No, a developer must prepare a configuration file and associate to it a user function,

D.
No, a graphical expression editor can be used to drag and drop columns and the
required function definitions.

Explanation: