Add and/or subract data values in form fields

Question

I'm trying to have a date value in one field calculated from another. For example Issue date field plus 90 days = Contract Due data field. Is there a way, maybe javascript to do this in a ADD form?
Thanks for any help,
Tony

Answer 1

Hi Tony,
instead of trying that with javascript, I´d rather create a Custom Trigger
(type: AFTER) which updates your table´s "contract_due" column by applying MySQL´s DATE_ADD function to ADDT´s transaction value
($tNG->getColumnValue("column_name")), like this:
"UPDATE tablename SET contract_due = DATE_ADD(".$tNG->getColumnValue("issue_date").",INTERVAL 90 DAY) WHERE primary_key_column = ".$tNG->getPrimaryKeyValue()."";
That should work, although I´m not sure if you would first have to convert the value of $tNG->getColumnValue("issue_date") back to a valid MySQL date format
(YYYY-MM-DD), in case the field "issue_date" displays the date in a different format, like e.g. DD.MM.YYYY
However I think that a javascript based approach should be avoided whenever possible, because even if that works, the user might modify the "contract_due" field value before submitting the data.
Cheers,
Günter Schenk
Adobe Community Expert, Dreamweaver