Question

what is primary key in a tables​

Answer 1

Answer:

A primary key is a special relational database table column (or combination of columns) designated to uniquely identify all table records. A primary key's main features are: It must contain a unique value for each row of data. It cannot contain null values.

Answer 2

Answer:

A Primary Key is a unique value that identifies a row in a table.

For ex- Student Table contains columns such as Admno, Name DOB Address, Phone can be considered as primary Key.