DataSetField is the FieldName of the TField object whose value this adapter field represents. DataSetField can be the name of a simple field in a database table, the name of a subfield of an object field that has been qualified by the parent field's name, or the name of an aggregated field. 

DataSetField is the same as the name of this adapter field in server-side script, except that the name of the adapter field omits any illegal characters (the only legal characters are the letters between a and z (or A and Z), digits, and the underline character). 

If DataSetField is an empty string, this adapter field does not have a value, and the FindField method returns nil (Delphi) or NULL (C++). 

FieldName 

FindField