How do I change a 1-1 relationship to 1-many? Both fields are calculated text and when I create a relationship it shows as 1-1.
make one side of the relastionship not a calculation or other field definition that has an index.
You can change the calculations so they match on multiple records and that will change the display in the TOG.
Showing 1-1 or 1-many is automatic and a condition of the actual fields and data used in the relationship. You don't make the TOG show what is there. FMP recognizes what is there and displayed it to you.
Building on what the others have said already: it is the nature of the data that will dictate whether the relationship is 1-1 or 1-many. There is nothing in the relationship setup itself that you can change to switch between the two.
There are two field options that cause a single line connector that indicates a "one" relationship:
Auto-entered serial numbers (on the auto-enter tab) and
the "unique values" setting (on the validation tab).
Retrieving data ...