Question

explain the use of primary key in a table​

Answer 1

Answer:

The PRIMARY KEY constraint uniquely identifies each record in a table. Primary keys must contain UNIQUE values, and cannot contain NULL values. A table can have only ONE primary key; and in the table, this primary key can consist of single or multiple columns (fields).

Answer 2

Explanation:

• The PRIMARY KEY constraint uniquely identifies each record in a table. Primary keys must contain UNIQUE values, and cannot contain NULL values.
• A table can have only ONE primary key; and in the table, this primary key can consist of single or multiple columns (fields).