Accessing serial values in a PowerBuilder script – PB Docs 2019

If you are connecting to an Informix database from a PowerBuilder
script, you can obtain the serial number of the row inserted into an
Informix table by checking the value of the SQLReturnData property of the
Transaction object.

After an embedded SQL INSERT statement executes,
SQLReturnData contains the serial number that uniquely identifies the row
inserted into the table.

PowerBuilder updates SQLReturnData following an embedded
SQL statement only; it does not update it following a DataWindow
operation.