A quick tip for beginning FileMaker developers from Richard Carlton: Updating contacts in a table by importing an Excel or CSV file. The one piece necessary for this to work is having a field in FileMaker that matches a field in the import sheet. Usually you can do this with an email address (as he does in this example), a phone number, the address, or something similar. While not perfect, if you are updating a lot of records, you could get most of the work done with a process like this:
If you have an Excel or CSV file you can easily import those records into FileMaker Pro. This demo shows how to remove invalid emails from an email campaign system that is run from FileMaker.
The video shows some good concepts: how to set a flag, how to make a relationship, and how to write a script to automate a process, among others.