i have a form with 3 fields. Start, Destination and Miles. When a user selects a starting location and an ending location, the mileage should be inserted into the mile field.



I have tables to represent the starting location, and within the table a list of possible destinations with a mileage attached to it. So for instance if i select "123 berry St" for my start and "wal-mart" for a destination. I need it to open the 123 berry St table. find wal-mart and return the mileage.
And how could get it to recognize if the table 123 berrySt. doesnt exist try looking for the reverse, walmart table/ 123 berry st. and return the mileage. or opt to create a new table?