# Category: Relational algebra

Relational algebra
In database theory, relational algebra is a theory that uses algebraic structures with a well-founded semantics for modeling data, and defining queries on it. The theory was introduced by Edgar F. Cod
String operations
In computer science, in the area of formal language theory, frequent use is made of a variety of string functions; however, the notation used is different from that used for computer programming, and
RAMiCS
RAMiCS, the International Conference on Relational and Algebraic Methods in Computer Science, is an academic conference organized every eighteen months by an international steering committee and held
Projection (relational algebra)
In relational algebra, a projection is a unary operation written as , where is a relation and are attribute names. Its result is defined as the set obtained when the components of the tuples in are re
Rename (relational algebra)
In relational algebra, a rename is a unary operation written as where: * R is a relation * a and b are attribute names * b is an attribute of R The result is identical to R except that the b attrib
Selection (relational algebra)
In relational algebra, a selection (sometimes called a restriction in reference to E.F. Codd's 1970 paper and not, contrary to a popular belief, to avoid confusion with SQL's use of SELECT, since Codd
Database normalization
Database normalization or database normalisation (see spelling differences) is the process of structuring a relational database in accordance with a series of so-called normal forms in order to reduce
Lossless join decomposition
In database design, a lossless join decomposition is a decomposition of a relation into relations such that a natural join of the two smaller relations yields back the original relation. This is centr
Has-a
In database design, object-oriented programming and design (see object oriented program architecture), has-a (has_a or has a) is a composition relationship where one object (often called the constitut