7 Essential PostgreSQL Constraints Every Developer Must Master for Data Integrity

PostgreSQL constraints apply to columns (or sets of columns) and stop the insertion of incorrect or inconsistent records into tables

constraints are Primary Key, Foreign Key, Unique, Check, Not Null, Exclusion, and Deferrable Constraints

Primary Key is among the most basic PostgreSQL constraints if you’re working with relational databases

A Foreign Key is a construct that establishes a link between two tables by making sure that the data in a column (or set of columns) is the same as the primary key column of the related table

The Unique constraint guarantees that all the values in a column (or combination of columns) are unique, i.e. there are no duplicates

A Check constraint is a condition or restriction that must be followed when a new row is inserted

The Not Null constraint is-one of the simplest yet the most essential constraints in a database