Best way to creat conditional value list in this instance?

[jim0203]

I'm creating a database for a company which fixes computers.

Whenever a customer comes into the company's shop, a record is added to a "session" table. This record includes a customer ID, computer ID, the time the session started, and the time it finishes (left blank until the session finishes, obviously).

I have another table called "session events". This table contains one record for every event that happens during the session: for example, "replaced motherboard", "installed filemaker" etc.

"session events" is linked to "session" via a session ID number, which is a serial number generated when a new session is created in "session". I want to create a conditional drop-down in "session events", that lists only those session ID numbers associated to events that are currently "open": i.e., those that exist in "session" but don't have a "session closed" time entered.

I'm a complete n00b as far as FM is concerned and although I've read through a number of tutorials and forum posts I'm none the wiser. There seems to be a number of ways I can do this, and I'm not sure which is the best way to proceed.

[mr_vodka]

Create a new calc.

Case ( IsEmpty ( session closed ); session ID )

Use that calc field in your value list.

[jim0203]

Thanks for that. Could you go into a little more detail? Like where I create the field, what I have to select when I specify the contents of the dropdown, etc? I would really appreciate it as I'm totally new to FM.

Many, many thanks. J.

[mr_vodka]

The calc is created in the session table. Then create your value list based off that calc field.

You can then attach the value list to layout based on seesion events.

[jim0203]

Thanks, that works perfectly.