Return the column names found in the input file.
The identifiers will only have a name but
no data type assigned as this information is not available in a text file.
If the input file does not contain a header row, the columns
will be named Column1, Column2, ...
the columns defined in the input file
Define the columns in the input file.
Parameters: columnList - the list of columns present in the input file throws: SQLException - if the columns could not be verified in the DB or the target table does not exist
Define the columns that should be imported.
If the list is empty or null, then all columns will be imported
Parameters: columnList - the columns to be imported