You chose short text, which was a good decision. The digits in the phone number won$$t be used for calculations so a Number data type is not needed.

It$$s really important that phone numbers are entered accurately in the table since they can be autodialed by customer service and sales representatives who need to reach a client. You decide to use a validity check that will ensure all client phone numbers, regardless of who enters them into the database, remain in the same format. What validity check will be most helpful for the phone number field?

Uniqueness check.

Format check with an input mask.