The relational model (RM) is an approach to managing data using a structure and language consistent with first-order predicate logic, first described in 1969 by English computer scientist Edgar F. Codd,[1][2] where all data is represented in terms of tuples, grouped into relations. A database organized in terms of the relational model is a relational database.
The purpose of the relational model is to provide a declarative method for specifying data and queries: users directly state what information the database contains and what information they want from it, and let the database management system software take care of describing data structures for storing the data and retrieval procedures for answering queries.
Most relational databases use the SQL data definition and query language; these systems implement what can be regarded as an engineering approximation to the relational model. A table in a SQL database schema corresponds to a predicate variable; the contents of a table to a relation; key constraints, other constraints, and SQL queries correspond to predicates. However, SQL databases deviate from the relational model in many details, and Codd fiercely argued against deviations that compromise the original principles.[3]
^Codd, E.F (1969), Derivability, Redundancy, and Consistency of Relations Stored in Large Data Banks, Research Report, IBM.
^Codd, E.F (1970). "A Relational Model of Data for Large Shared Data Banks". Communications of the ACM. Classics. 13 (6): 377–87. doi:10.1145/362384.362685. S2CID 207549016. Archived from the original on 2007-06-12.
^Codd, E. F (1990), The Relational Model for Database Management, Addison-Wesley, pp. 371–388, ISBN 978-0-201-14192-4.
The relationalmodel (RM) is an approach to managing data using a structure and language consistent with first-order predicate logic, first described in...
A relational database (RDB) is a database based on the relationalmodel of data, as proposed by E. F. Codd in 1970. A database management system used...
database model is the relationalmodel, which uses a table-based format. Common logical data models for databases include: Hierarchical database model This...
Relationalmodels theory (RMT) is a theory of interpersonal relationships, authored by anthropologist Alan Fiske and initially developed from his fieldwork...
systems according to the database models that they support. Relational databases became dominant in the 1980s. These model data as rows and columns in a series...
proposed by British computer scientist Edgar F. Codd as part of his relationalmodel. Normalization entails organizing the columns (attributes) and tables...
The nested set model is a technique for representing nested set collections (also known as trees or hierarchies) in relational databases. It is based...
hierarchies over the same data. The hierarchical data model lost traction as Codd's relationalmodel became the de facto standard used by virtually all mainstream...
relational calculus consists of two calculi, the tuple relational calculus and the domain relational calculus, that is part of the relationalmodel for...
languages to use Edgar F. Codd's relationalmodel. The model was described in his influential 1970 paper, "A RelationalModel of Data for Large Shared Data...
In database theory, relational algebra is a theory that uses algebraic structures for modeling data, and defining queries on it with a well founded semantics...
First normal form (1NF) is a property of a relation in a relational database. A relation is in first normal form if and only if no attribute domain has...
Statistical relational learning (SRL) is a subdiscipline of artificial intelligence and machine learning that is concerned with domain models that exhibit...
or "non-relational") is an approach to database design that focuses on providing a mechanism for storage and retrieval of data that is modeled in means...
Information Modeling RelationalModelRelationalModel/Tasmania Generic data models are generalizations of conventional data models. They define standardized...
data model (organization of data in a database) which does not meet any of the conditions of database normalization defined by the relationalmodel. Database...
Codd as part of the relationalmodel, in order to provide a declarative database-query language for data manipulation in this data model. It formed the inspiration...
1970s before being widely replaced by relational databases in the 1980s. While the hierarchical database model structures data as a tree of records, with...
databases. Also in the 2010s, multi-model databases that supported graph models (and other models such as relational database or document-oriented database)...