SQL Constraints (Image by - Sharma Guides | Subham232330) Constraints | |- CHECK | |- NOT NULL | |- UNIQUE | |- PRIMARY KEY | |- DEFAULT | |- FOREIGN KEY | |- INDEX * These constraints are also known as Integrity Constraints . * SQL Constraints:- Constraints are the rules and restrictions applied to the data in a table. * NOT NULL:- Value cannot be Null in a column. * UNIQUE:- Value cannot be the same in a column. * PRIMARY KEY:- Used to uniquely identify a row. * FOREIGN KEY:- References a row in another table. * CHECK:- Satisfies a specific condition. * DEFAULT:- Set default value. * CREATE INDEX:- Used to speed up the reading process.