Hello.

I am building a vet clinic app, in which I need to make sure there are no appointments being made for the same doctor at the same time of an already existing appointment.

Example:

Doctor1 has an appointment for 01/10/2019 at 10am. I need to display an error if I try to insert another appointment for the same doctor at the same date and time. But if 1 of the 3 properties is different, it should be added.

So basically what I need to know is how can I make a combination of 3 variables unique?

Thanks in advance,