Why ID

Question

In this example wouldn't the phone numbers be enough to differentiate the different people, as the numbers can't be the same? I'm guessing that it's always convenient to have the ID but, is it necessary?

Answer 1

where is your example?

okay, by my understanding,

Phone numbers will be unique, but not in sorted order,

if you used id, then it will automatically incremented,

eg:-
if you want to do something with first ten entries, then you can't do it by phone numbers, but it can be done if there is ID

Also, if in any company,
phone numbers maybe same for both guys like husband and wife if there is only one phone in their house, so if there is ID they will be differentiated!!

These are my experiences, while I worked with SQL

Answer 2

Thanks very much.

My example is in 'Introduction to Databases' the third explanation.