What is relational algebra?

Relational algebra is a formal system that provides a set of operations to manipulate and query relational databases. It is foundational to the understanding of how databases function and is used to express queries in relational database management systems. The operations defined by relational algebra, such as selection, projection, union, intersection, and join, enable users to retrieve and combine data from different tables in a structured way.

This formal system is not related to encrypting data, which focuses on securing information rather than manipulating it. It also differs from database normalization, which is a design approach to minimize redundancy and dependency within databases. While relational algebra may guide the process of forming SQL queries due to its influence on query logic, it does not serve as a set of guidelines specifically for writing SQL statements. Instead, it lays a theoretical groundwork that is often translated into practical query languages like SQL. Thus, the essence of relational algebra is its role as a formal language for defining operations on relational data sets.