In relational algebra, a projection is a unary operation written as Π a 1 , . . . , a n ( R ) {\displaystyle \Pi _{a_{1},...,a_{n}}(R)} , where R {\displaystyle...

In database theory, relational algebra is a theory that uses algebraic structures for modeling data and defining queries on it with well founded semantics...

projection of a vector onto a straight line Projection (relational algebra), a type of unary operation in relational algebra Projective geometry, the study of geometric...

Idempotent linear transformation from a vector space to itself Projection (relational algebra) – Operation that restricts a relation to a specified set of...

evaluation map is a projection map from the Cartesian product.[citation needed] For relational databases and query languages, the projection is a unary operation...

A relational database (RDB) is a database based on the relational model of data, as proposed by E. F. Codd in 1970. A database management system used...

The relational model (RM) is an approach to managing data using a structure and language consistent with first-order predicate logic, first described in...

Imieliński–Lipski algebras are defined to satisfy precise conditions for semantically meaningful extension of the usual relational operators, such as projection, selection...

0-tuple.:56 The zero-degree relations represent true and false in relational algebra.:57 Under the closed-world assumption, an n-ary relation is interpreted...

In mathematics and abstract algebra, a relation algebra is a residuated Boolean algebra expanded with an involution called converse, a unary operation...

the relational algebra projection operation. AS optionally provides an alias for each column or expression in the SELECT list. This is the relational algebra...

= { x ∈ X : x ∼ a } . {\displaystyle [a]=\{x\in X:x\sim a\}.} In relational algebra, if R ⊆ X × Y {\displaystyle R\subseteq X\times Y} and S ⊆ Y × Z {\displaystyle...

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...

The projection of a string is essentially the same as a projection in relational algebra. String projection may be promoted to the projection of a language...

of information algebras: Relational algebra: The reduct of a relational algebra with natural join as combination and the usual projection is a labeled information...

is a normal form used in relational database normalization which extends the relational algebra and generalizes relational operators (such as join) to...

Predicate (mathematical logic) Projection (set theory) Reflexive relation Relation algebra Relational algebra Relational model Relations (philosophy) Codd...

In algebra, a homomorphism is a structure-preserving map between two algebraic structures of the same type (such as two groups, two rings, or two vector...

a pi bond. The natural projection on the tangent bundle on a manifold. The unary operation of projection in relational algebra. Policy in reinforcement...

and (in the last case) uniqueness of certain lifts. In algebraic topology and homological algebra, tensor product and the Hom functor are adjoint; however...

the product operator in mathematics a plane the unary projection operation in relational algebra the Pi function, i.e. the Gamma function when offset to...

Kripke semantics (also known as relational semantics or frame semantics, and often confused with possible world semantics) is a formal semantics for non-classical...

Signatures, TensorFaces TensorTexures and Multilinear Projection. Multilinear algebra, the algebra of higher-order tensors, is a suitable and transparent...

relations for n ≥ 2 , {\displaystyle n\geq 2,} is the join operation of relational algebra. The usual composition of two binary relations as defined here can...

sinusoidal projection and the Bonne projection. The Werner projection places its standard parallel at the North Pole; a sinusoidal projection places its...

by the creator of the relational database model, E. F. Codd, SQL null serves to fulfil the requirement that all true relational database management systems...

Haskell records. Relational databases may formally identify their rows (records) as tuples. Tuples also occur in relational algebra; when programming...

systems. If there are relational data streams and the logical query plan is based on relational operators from the Relational algebra, a query optimizer...

≤ {\displaystyle \,\leq \,} will suffice to denote the corresponding relational symbol, even without prior introduction. Furthermore, < will denote the...

direct product, Kronecker product, categorical product, cardinal product, relational product, weak direct product, or conjunction. As an operation on binary...