Is the primary key and auto increment the same?&??

Answer 1

no but it can be auto increment has all they basic property required for a primary key but it can be case that
there are more than one auto increment columns or more than one distinct columns . here only one will be primary

Answer 2

A column can definitely be an identity without being a PK.

An identity is simply an auto-increasing column.

A primary key is the unique column or columns that define the row.

These two are often used together, but there's no requirement that this be so.

Answer 3

The answer is no. For example you can create a table with passport number as primary key and without auto-increment condition. But when you want to create and ID column to sequentially identify each row is better to use auto increment than doing by yourself.

Answer 4

Yes and Not.
Autoincrement can only be the primary key;
but primary key can be other such as social id