Imposition of Constraints | Dr.S.Kalaiselvi | Department of Computer Science
Imposition of Constraints in SQL
In this technical session, Dr. S. Kalaiselvi from the Department of Computer Science explains the critical role of Constraints in maintaining database integrity. Constraints are the rules enforced on data columns to ensure the accuracy, reliability, and validity of the information stored within a relational database.
This lecture covers how to effectively "impose" these rules during table creation and modification to prevent invalid data entry and maintain a high-quality data environment.
What You Will Learn:
Understanding Constraints: Why constraints are necessary for data consistency and business logic enforcement.
Key Types of Constraints:
NOT NULL: Ensuring a column cannot have an empty value.
UNIQUE: Guaranteeing that all values in a column are distinct.
PRIMARY KEY: Uniquely identifying each record in a table.
FOREIGN KEY: Maintaining referential integrity between related tables.
CHECK: Ensuring that all values in a column satisfy a specific condition.
DEFAULT: Providing a preset value when none is specified.
The Imposition Process: How to apply constraints using CREATE TABLE and ALTER TABLE statements.