The article discusses relational algebra, a mathematical system used in computer science for working with databases. It deals with operations on sets of relations to retrieve specific information. Relational algebra is closely related to relational calculus and first-order logic, and was developed by E.F. Codd as a foundation for database query languages. Codd introduced restrictions to ensure the algebra's practicality for database use, such as limiting operations to finite relations and providing limited support for negation and disjunction. Despite these restrictions, relational algebra remains a powerful tool for database management.