A relational database is a database that stores and provides access to data points that are related to each other. Relational databases are based on the relational model, which is an intuitive and straightforward way of representing data in tables.

A relational database, as proposed by E. F. Codd in 1970, is a (most commonly numerical) database based on a data relational model. [1] The system used to maintain a relational database is a relational database management system (RDBMS). Many relational database systems are equipped with the option to query and update the database using SQL (Structured Query Language).

The term "relational database" was first defined by IBM's E. F. Codd in 1970. Codd introduced the term in his research paper "Data Relational Models for Large Shared Databases". [3] In this and subsequent papers, he defines what is meant by "relationship". A well-known definition of a relational database system consists of Codd's 12 rules. However, no commercial implementation of the relational model conforms to all of Codd's rules,[4] so the term has come to be used to describe a broader class of database systems, at least:

The most common definition of an RDBMS is a product that presents a view of data as a collection of rows and columns, even if it is not strictly based on relational theory. By this definition, RDBMS products typically implement some, but not all, of Codd's 12 rules.