difference between primary key unique constraints

Dear aspirant,

These are some differences:-

Primary key: 1.   A primary key is a column of table which uniquely identifies each tuple (row) in that table.

2.    Primary key enforces integrity constraints to the table.

3.   Only one primary key is allowed to use in a table.

4.   The primary key does not accept the any duplicate and NULL values.

Unique key: 1. Unique key constraints also identifies an individual tuple uniquely in a relation or table.

2.  A table can have more than one unique key unlike primary key.

3. Unique key constraints can accept only one NULL value for column.

4. Unique constraints are also referenced by the foreign key of another table.

*I hope this information helps you.

Hello sahil varpe,

Good morning,

i am here to help u.The primary key is a column of table which uniquely indentifies each row in the table.primary key enforces integrity constraints to the table only one primary key is allowed to use in a table.

The difference between a unique constraint a primary key can defines more than one unique constraints.Primary key constraints  are not nullable.unique constraints may be nullable.

when you create a unique constraint, the database automatically creates unique index.

This information may help u,

thank you,

Have a nice day.