In relational algebra, a projection is a unary operation written as Πa1,...,an(R){\displaystyle \Pi _{a_{1},...,a_{n}}(R)}, where R{\displaystyle R} is...

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

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

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...

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 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...

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

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

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

topology to calculus of relations in their book Relational Topology. They aim "to lift concepts to a relational level making them point free as well as quantifier...

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

the product operator in mathematics a plane the unary projection operation in relational algebra osmotic pressure π {\displaystyle \pi } represents: Archimedes'...

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...

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...

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

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

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

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

were then re-formulated by Grigore Constantin Moisil in an axiomatic algebraic form, and also extended to n-valued logics in 1945. Around 1910, Charles...

community to recognize the connection between Codd's relational algebra and Tarski's cylindric algebras were Witold Lipski and Tomasz Imieliński, in a talk...

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

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

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...