Basic question about relationship graph

[Matthew F]

My Filemaker User manual explains that the match field in a single criteria relationship is connected to its related table by a single thin line if only a single record can match (e.g. a serial number). The line connecting match fields has a little "fork" symbol on the end if it is possible to match multiple records.

What does it mean when the line connecting Match Fields has a little "T" at the end? I have some tables with this symbol and they don't seem to work.

Thanks!

[-Queue-]

It means the relationship only goes one way. The field with the "T" cannot be used as the child key, only the parent key. It is either a global or unstored calculation field which cannot be indexed.