Answers for "What does a primary key do?"

SQL

4

what is primary key

Primary Key :
It is unique column in every table in a database
It can ONLY accept;
    - nonduplicate values
    - cannot be NULL



Foreign Key: 
It is a column that comes from a different table and
using Foreign key tables are related each other
It is the primary key of another table
It can be duplicate or null for another table




Unique Key:
Only unique value and also can contain NULL

Posted by: Guest on January-27-2021

Code answers related to "What does a primary key do?"

Code answers related to "SQL"

Browse Popular Code Answers by Language

Python

Javascript

Whatever

Shell/Bash

CSS

Html

PHP

SQL

Java

C#