SCT DBD Overlay Conventions
The following record types are used in the overlay process:

Record Type | Description
DF | For file determination.
DS | To parse record segments.
DC | To populate the comment field in the CONNX CDD.
DE | To populate the DBD field name in the CONNX CDD.
DY | To populate the DBD field name if no DBD record is found.

Each field can be renamed once, based on the offset and record segment. Subsequent field names for the same offset and length are ignored.
The DE record is used to parse the segment if the SCT table has a SQL view clause in the CONNX CDD for the relevant table.
If a segment indicator is found in the DS record, the dynamic array offset is used to calculate the field offset being renamed.
All comments that begin with the words FOCUS or RECORD COPY are ignored.
All comments are truncated to the first 250 characters.
Any field containing the word FILLER is not renamed although the comments are applied to all FILLER fields that have comments in the DBD.