I have 3 tables --Ticket_Lines (parent), Labour_Items (child), Part_Items (child).
Table Ticket_Lines has 2 primary keys (ticket_number & ticket_line_number)
I know that you cant have two seperate primary keys in one table so would this mean that ticket_number and ticket_line_number is a composite primary key?
if that is correct, is this the best way of defining a composite primary key?
CONSTRAINT PRIMARY KEY (ticket_number, ticket_line_number);