DROP PRIMARY KEY IN SQL

PRIMARY KEY in SQL

PRIMARY KEY in SQL is a column (or group of columns) that uniquely identifies the records in that table. A primary key must contain unique values and can not have any NULL value....

Syntax

There are two syntaxes to create/add primary key to a table:...

SQL PRIMARY KEY Examples

Let’s look at some examples of the PRIMARY KEY Constraint in SQL, and understand it’s working....

DROP PRIMARY KEY IN SQL

To remove a primary key from the table use the ALTER TABLE STATEMENT with DROP PRIMARY KEY clause....

Important Points About SQL PRIMARY KEY

A primary key is a column or a set of columns in a table that uniquely identifies each row. It ensures data integrity by preventing duplicate records and null values. A primary key can be defined on a single column (simple primary key) or multiple columns (composite primary key). Creating a primary key automatically creates a unique index on the key column(s), improving query performance. Establishing relationships between tables using SQL primary key and foreign key improve database design, reduce data redundancy, and improve data consistency....