Primary Key Concepts in Database

Primary key:
Every record in a file should contain at least one field that uniquely identifies that record so that the record can be retrieved, updated, or sorted.

A primary key is one or more fields (columns) whose values uniquely identify each record in a table.
A primary key cannot allow Null values and must always have a unique index.

Видео Primary Key Concepts in Database канала Md. Zahidul Hasan