Integrity Constraint Violation - SYS_FK_129

[Martin Petty]

I am creating a database to manage tickets for a music festival. I have 3 tables, People, Events and Tickets with 1-many relationships between People and Tickets and Events and Tickets. I have managed to create a data entry form and insert list boxes that give a drop down of the events and people. All seemed fine until I tried entering a ticket.

I can't get passed
"Integrity constraint violation - no parent SYS_FK_129 table: Tickets in statement [UPDATE "Tickets" SET "EVENT NAME" = ?, "Name" = ? WHERE "Ticket Number" = ? ]

Any help with the immediate problem or advice on a better way of achieving the desired result will be welcome.

The relationships all have a field type INTEGER and a little SQL (SELECT "Event Name", "Event Name" FROM "Events") is used to provide the list box with people's or event's names. I don't know if this is part of the problem or not.