@tpartner customer proffers option with Array, and it seems to work good apart from the fact, that currently we can't pass validation.
I've attached screenshot with explanation.
1 table question is "How often do you listen to particular stations"
And replies are:
"I don't know this station"
"I know this station but never listen"
"sometimes"
and so on...
Question in second table is: "If placed by importance which station is your number 1, number 2.... number 4 priority when choosing what to listen to?"
And we can have only 4 answers there, each unique. But in the end of the table we have this "NO REPLY" option for stations which people listen to, but dont want to rate.
We are using this validation rule: unique(self) and it breaks on this "no reply" field. Is there a way to remove "no reply" field from unique(self) rule?
For second table we disable all rows, which are "I don't know this station".