Question

What is primary key and write its types.

Answer 1

Answer:

Difference Between Primary key & Foreign key

Primary Key Foreign Key

Helps you to uniquely identify a record in the table. It is a field in the table that is the primary key of another table.

Primary Key never accept null values. A foreign key may accept multiple null values.

Answer 2

$\huge\underbrace\mathfrak\‌red{Answer}$

Primary Key - The primary key is selected from one of the candidate keys and becomes the identifying key of a table. It can uniquely identify any data row of the table.

Type of primary key: Super Key - Super Key is the superset of primary key.