Search results
Results From The WOW.Com Content Network
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 ...
A relational database ( RDB[ 1]) is a database based on the relational model of data, as proposed by E. F. Codd in 1970. [ 2] A database management system used to maintain relational databases is a relational database management system ( RDBMS ). Many relational database systems are equipped with the option of using SQL (Structured Query ...
A database model is a type of data model that determines the logical structure of a database. It fundamentally determines in which manner data can be stored, organized and manipulated. The most popular example of a database model is the relational model, which uses a table-based format.
Relational algebra is a branch of mathematics that studies the manipulation and analysis of data in relational databases. It defines a set of operations, such as selection, projection, join, and union, that can be applied to relations or sets of tuples. Learn more about the concepts and notation of relational algebra on Wikipedia, including the rename operation that changes the attribute name ...
Database normalization is the process of structuring a relational database in accordance with a series of so-called normal forms in order to reduce data redundancy and improve data integrity. It was first proposed by British computer scientist Edgar F. Codd as part of his relational model . Normalization entails organizing the columns ...
Codd's twelve rules[ 1] are a set of thirteen rules ( numbered zero to twelve) proposed by Edgar F. Codd, a pioneer of the relational model for databases, designed to define what is required from a database management system in order for it to be considered relational, i.e., a relational database management system (RDBMS). [ 2][ 3] They are ...
Entity–relationship model. An entity–attribute-relationship diagram for an MMORPG using Chen's notation. An entity–relationship model (or ER model) describes interrelated things of interest in a specific domain of knowledge. A basic ER model is composed of entity types (which classify the things of interest) and specifies relationships ...
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 relations as elements. [ 1] Or more informally, that no table column can have tables as values. Database normalization is the process of representing a database in terms of relations in ...