APEX Data Load Definition Questions

APEX Build 19.2.0.00.18, Oracle EBS 12.2.10

We have an APEX application that takes a tab delimited text file generated in an outside application and uploads it to a custom staging table in Oracle. The current file has an ID field at the end of the file, but no values. The APEX application has a data transformation rule that generates a sequence for each record upon load. The file contains headings for each field. The problem we now have is the outside application has been changed and it generates the file, but with no ID column at the end. The APEX application