For each external table, a single row exists in the sysexternal system catalog table.

The tabid column associates the external table record in this system catalog table with an entry in systables.
Column Type Explanation
tabid INTEGER Unique identifying code of an external table
fmttype CHAR(1) Type of format: D = (delimited) F = (fixed) I = (HCL OneDB™)
codeset VARCHAR(128) Reserved for future use
recdelim VARCHAR(128) The record delimiter
flddelim CHAR(4) The field delimiter
datefmt CHAR(8) Reserved for future use
moneyfmt CHAR(20) Reserved for future use
maxerrors INTEGER Number of errors to allow
rejectfile CHAR(464) Name of the reject file
flags INTEGER Optional load flags
ndfiles INTEGER Number of data files in sysextdfiles

You can use the dbschema utility to write out the description of the external tables. To query these system catalog tables about an external table, use the tabid as stored in systables with tabtype = ‘E'.

An index on the tabid column allows only unique values.