Constraint used in SQL- Indian Bro Code
In SQL, constraints are rules applied to columns in a table to ensure the integrity, accuracy, and reliability of the data in the database. Constraints define how data is entered, updated, and deleted, and they help prevent incorrect or inconsistent data from being stored.
NOT NULL - Ensures that a column cannot have a NULL value
UNIQUE - Ensures that all values in a column are different
PRIMARY KEY - A combination of a NOT NULL and UNIQUE. Uniquely identifies each row in a table
FOREIGN KEY - Prevents actions that would destroy links between tables
CHECK - Ensures that the values in a column satisfies a specific condition
DEFAULT - Sets a default value for a column if no value is specified
CREATE INDEX - Used to create and retrieve data from the database very quickly