SQL PRIMARY KEY Constraint
SQL PRIMARY KEY Constraint
The PRIMARY KEY constraint uniquely identifies each record in a database table.Primary keys must contain UNIQUE values.
A primary key column cannot contain NULL values.
Most tables should have a primary key, and each table can have only ONE primary key.
Read more: SQL UNIQUE Constraint
Ввійдіть щоб вподобати
Ввійдіть щоб прокоментувати