Database Constraints
Database constraints are rules enforced on data columns in a database to ensure data integrity, accuracy, and consistency. They define conditions that data must satisfy, such as uniqueness, non-null values, or relationships between tables, preventing invalid data entry and maintaining reliable database operations. Common types include primary keys, foreign keys, unique constraints, check constraints, and not-null constraints.
Developers should use database constraints to enforce business rules directly at the database level, reducing application-level errors and ensuring data quality across all applications accessing the database. They are essential for maintaining referential integrity in relational databases, preventing orphaned records, and supporting data validation in scenarios like e-commerce transactions or user account management. Constraints also improve query performance by enabling efficient indexing and data retrieval.