relational algebra

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relational algebra

(database, theory)
A family of algebra with a well-founded semantics used for modelling the data stored in relational databases, and defining queries on it. The main operations of the relational algebra are the set operations (such as union, intersection, and cartesian product), selection (keeping only some lines of a table) and the projection (keeping only some columns).

The relational data model describes how the data is structured.

Codd's reduction algorithm can convert from relational calculus to relational algebra.

relational algebra

(1) The branch of mathematics that deals with relations; for example, AND, OR, NOT, IS and CONTAINS.

(2) In a relational database, a collection of rules for dealing with tables; for example, JOIN, UNION and INTERSECT.
References in periodicals archive ?
Another unexplored and, we believe, promising research direction is the application of our framework of operator tree / query graph / association tree to reorder other operators that combine relations, such as semijoin and antijoin.