AS/400 SQL queries can be processed inside transaction.
Use regular WinDev transaction functions:
sStmt is string
MyQuery is Data Source
SQLTransaction(sqlStart,MyConnection)
sStmt="UPDATE SP_CUST SET Firstname='Jean' WHERE CUST_ID='C-01'"
HExecuteSQLQuery(myQuery,MyConnection,hQueryDefault,sStmt)
SQLTransaction(sqlRollBack,MyConnection)