There are basic 3 Keys in SQL:
Primary Key (PK) – Primary Key is an attribute which uniquely defines the row in a database. It is an attribute about a specific entry.
Foreign Key (FK) – Foreign Key is basically an attribute that we can store in a database table that will link us to another database table.
Composite Key (CK) – Composite Key is a key that needs 2 attributes to uniquely identify each row. Here we define 2 columns as primary key.
Published By : Sushmita Mandal