Relational database

A relational database is a database based on the relational model. Strictly speaking the term refers to a specific collection of data but it is invariably employed together with the software used to manage that collection of data. That software is more correctly called a relational database management system, or RDBMS.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

All data which is stored in and retrieved from a relational database is cast in the form of relations. A relation is a set of n-tuples that represents the extension of an n-adic predicate. However, these n-tuples are not the ordered tuples of mathematics; instead, their components, called attribute values, are identified and referenced by names. Queries and integrity constraints are expressed declaratively, without the use of iterative loops or pointers, using operators based on the relational algebra and relation comparisons. The relational algebra is complete with respect to first-order predicate calculus except that certain restrictions are imposed on the use of negation and disjunction to address problems of computability.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Database: A database is an organized collection of data. The term originated within the computer industry, but its meaning has been broadened by popular use, to the extent that the European Database Directive (which creates intellectual property rights for databases) includes non-electronic databases within i...

Relational model: The relational model for management of a database is a data model based on predicate logic and set theory....

Data: Data is the plural of datum....