I have set up a relationship between three tables on the field 'Name'. The two related tables are set up as portals. The problem occurs when I modify the contents of the 'Name' field in a record--the portal data disappears. If I change the name back to the original name, the portal data reappears. I don't know if it's a problem with the way I set up the relationship, or if there's an option that should be checked/unchecked?

Any help appreciated.

What you're seeing is entirely normal: if you change the value of one of the key fields used in a relationship then you're asking the relationship to find the 'name' records in the child table that match the value in 'name' in the parent. If there aren't any then the portal will be empty.

What is it that you expected? Then we can tell you if you can set up your relationship differently

Think of the matching child record set as doing a find in that related table for all 'names' that match what you have in the parent table.