A formal definition of the relational model
C. J. Date · ACM SIGMOD Record · 1982
The relational model of data, originally introduced by Codd in [1], has three components: (1) a set of objects (relations, domains, etc.); (2) a set of operators (union, project, etc.); (3) a set of general integrity rules. The purpose of this paper is to provide a formal definition of each of these three components.