The Primary Key constraint

The syntax to when creating a primary key in [[The CREATE statement]]:

CREATE TABLE table_name (
column_name data_type,
...
 PRIMARY KEY (column_name)
);

The syntax when changing the primary key in [[The ALTER statement]]:

ALTER TABLE table_name 
ADD PRIMARY KEY (column_name);

The syntax when dropping the primary key constraint using [[The DROP statement]]:

ALTER TABLE table_name
DROP PRIMARY KEY;