Can someone please point me in the right direction - where to look this up
Won't you have multiple postcodes for a given town? (That's how it works in the US, anyway)
Is is it also possible to have two different Towns with the same name? (I grew up in a small town, and happen to know that there are several towns across the country with the same name, but in different states.)
Whatever you desing here will have to handle such complications if they apply to your part of the world.
One approach is to use a conditional value list where selecting a town or a town and a state, results in a value list for the postcode field conditionally filtering down to just the postcodes for that one town.
This was only an example, I created this small database to workout how to do lookups. I was actually going to use what I learnt in a large database invoicing system.
Yet the same issues can apply in some circumstances.
Here's a thread that discusses two different approaches. Both can have their uses in the same Invoicing situation so you have to understand how they work and why one might be the better choice before you implement one method or the other:
Yes, Yes ,Yes - thank you very much for this. I now have my head around it. In my test the lookup was based on the town as a value list, but I neded to value list the ID (the relationship) and then look-up the other fileds I needed.
Thank you again
For looking up data, sometimes basing the relationship on a name makes for nicer options that using the ID. But if you go that route extra care has to be taken to handle the possibility of duplicate values and name changes.
Here's a demo file with an auto-complete enabled value list of names that looks up an ID so as to link the current record to a related table by ID:
FileMaker 12 users: https://dl.dropbox.com/u/78737945/SimpleNameLookupDemo.fmp12
Pre FileMaker 12 Users: https://dl.dropbox.com/u/78737945/SimpleNameLookupDemo.fp7
Thank you again - this is very interesting. I was looking at a relational tutorial on YouTube along these lines, but little was explained. This seems to tie the lose ends together for me.
Thanks heaps for this