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In computer science, a relational operator is a programming language construct or operator that tests or defines some kind of relation between two entities. These include numerical equality ( e.g. , 5 = 5 ) and inequalities ( e.g. , 4 ≥ 3 ).
The relational algebra uses set union, set difference, and Cartesian product from set theory, and adds additional constraints to these operators to create new ones.. For set union and set difference, the two relations involved must be union-compatible—that is, the two relations must have the same set of attributes.
In programming languages, scientific calculators and similar common operator notation or operator grammar is a way to define and analyse mathematical and other formal expressions. In this model a linear sequence of tokens are divided into two classes: operators and operands.
Relational concept, a set of mathematically defined tuples in tuple relational calculus; Relational model, a database model based on first-order predicate logic; Relational operator, a programming language construct or operator that tests or defines some kind of relation between two entities
In computer programming, operators are constructs defined within programming languages which behave generally like functions, but which differ syntactically or semantically. Common simple examples include arithmetic (e.g. addition with + ), comparison (e.g. " greater than " with > ), and logical operations (e.g. AND , also written && in some ...
In database theory, a conjunctive query is a restricted form of first-order queries using the logical conjunction operator. Many first-order queries can be written as conjunctive queries. In particular, a large part of queries issued on relational databases can be expressed in this way.
APL uses the term operator in Heaviside’s sense as a moderator of a function as opposed to some other programming language's use of the same term as something that operates on data, ref. relational operator and operators generally.
Datalog is a database definition language, which combines a relational view of data, as in relational databases, with a logical view, as in logic programming. Relational databases use a relational calculus or relational algebra, with relational operations , such as union , intersection , set difference and cartesian product to specify queries ...