Look Up another field and calculations

[Field]

I want to produce a field that automatically calculates the distance between two locations based on the postcode. The two loctions are in different databases (client & candidate).

Problem:

How do I create a field in the candidate database that will look up a value in a third database(postcodes) based on the postcode field in the candidate database?

I have created the database for postcodes but need the field in the candidate database to lookup a value based on his/her postcode.

basically i need a calculation that will tell filemaker to " use the postcode field in this record in the candidate database to get a value from the postcode database and put this value into a new field in the candidate database".

Clear as mud eh?

Any help and guuidance will be appreciated.

[Fitch]

Create a relationship between candidate and postcodes based on the postcode. Once that's done, you can use it for lookups, or you can display the data directly without a lookup.

I.e., if you have client->candidate->postcode, you can see the postcode info in the client file; you don't have to first "pipeline" it into the candidate file, the way we used to do in FileMaker 6.