How to add rules/conditions to adding table?

You would need to use a custom form for that.

If it’s just a date and not including the time, you can:

  • Convert the chosen date to numerical value (say have a math column to convert it to MMDDYYYY).

  • Do the same process in the table where you store existing reservations.

  • Create a relation from the chosen date’s numerical value to the existing reservation dates’ numerical values.

  • If the relation is not empty, then don’t allow them to add a row.

The process is much trickier when you add the time in, with periods of time.

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