The INPUT statement provides control blocks to allow your program to
initialize field contents and validate user input when adding a new row.
INPUT Statement Control blocks
Control blocks BEFORE FIELD and ON CHANGE are called automatically during an INPUT as the user moves the cursor through the fields of a form.
Module custmain.4gl
The MENU statement in the module custmain.4gl is modified to call functions for adding, updating, and deleting the rows in the customer table.
Module custquery.4gl (function inpupd_cust)
A new function, inpupd_cust, is added to the custquery.4gl module, allowing the user to insert values for a new customer row into the form.