What is the purpose of Oracle constraints?

Oracle constraints are rules or conditions used to ensure the integrity and consistency of data in a table. They can restrict the type, size, and format of data in a table, as well as enforce relationships and consistency between data. By defining constraints, errors in data input, data incompleteness, or inconsistency can be avoided, thereby improving the quality and reliability of data. Oracle constraints include primary key constraints, foreign key constraints, unique constraints, not null constraints, and check constraints.