PostgreSQL constraints protect data integrity by enforcing rules on inserted and updated rows. Learn how NOT NULL, UNIQUE, PRIMARY KEY, FOREIGN KEY and CHECK differ. Constraints are the rules that enforced on the data columns of a table. This ensures the accuracy and reliability of the data in the database. It maintains the integrity of data in the table. Levels of Constraints in SQL Constraints could be on a column… Read More »PostgreSQL Constraints Explained: PRIMARY KEY, FOREIGN KEY and CHECK