CLEO EDI Integrator has the ability to lookup data outside of the EDI data we received (inbound) or outside our CLEO Fileset (outbound):
Below are the types of External File lookups:

• Maintainable: This is where we can update a file to maintain inbound/outbound values. A good example is where we want to collect unique values, ie. inbound EDI PO # or outbound EDI invoice #. This files can also be used to just hold data for the current transaction.
• Maintain with rollback: This is would be the Physical/Logical File that we update to reflect a transaction has been processed. If there is an error, the update will be reversed.
• Normal Lookup: Normal External File Lookup in CLEO. No error will occur if data is not found.
• Required lookup: Normal External File Lookup in CLEO. A forced EXTOL generation/translation error will occur if data is not found.