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Domain Calculus
In computer science, domain relational calculus (DRC) is a calculus that was introduced by Michel Lacroix and Alain Pirotte as a declarative database query language for the relational data model.Michel Lacroix, Alain PirotteDomain-Oriented Relational Languages VLDB 1977: 370-378 In DRC, ''queries'' have the form: : \ where each Xi is either a domain variable or constant, and p(\langle X_1, X_2, ...., X_n \rangle) denotes a DRC ''formula''. The result of the query is the set of tuples X1 to Xn that make the DRC formula true. This language uses the same operators as tuple calculus, the logical connectives ∧ (and), ∨ (or) and ¬ (not). The existential quantifier (∃) and the universal quantifier (∀) can be used to bind the variables. Its computational expressiveness is equivalent to that of relational algebra. E. F. CoddRelational Completeness of Data Base Sub-languages In R. Rustin, editor, Data Base Systems. Prentice Hall, 1972 Examples Let (A, B, C) mean (Rank, N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Science
Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to Applied science, practical disciplines (including the design and implementation of Computer architecture, hardware and Computer programming, software). Computer science is generally considered an area of research, academic research and distinct from computer programming. Algorithms and data structures are central to computer science. The theory of computation concerns abstract models of computation and general classes of computational problem, problems that can be solved using them. The fields of cryptography and computer security involve studying the means for secure communication and for preventing Vulnerability (computing), security vulnerabilities. Computer graphics (computer science), Computer graphics and computational geometry address the generation of images. Progr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alain Pirotte
Alain may refer to: People * Alain (given name), common given name, including list of persons and fictional characters with the name * Alain (surname) * "Alain", a pseudonym for cartoonist Daniel Brustlein * Alain, a standard author abbreviation used to indicate Henri Alain Liogier, also known as Brother Alain, as the author when citing a botanical name * Émile Chartier (1868–1951), French philosopher and antimilitarist commonly known as Alain Places * Alain, Iran, a village in Tehran Province, Iran * Al Ain, a city in Abu Dhabi, United Arab Emirates ** Al Ain International Airport in the United Arab Emirates * Val-Alain, Quebec, village of 950 people in Quebec, Canada Other uses * 1969 Alain (1935 CG), a Main-belt Asteroid discovered in 1935 * ''Alain'' (crab), a genus of crabs in the family Pinnotheridae * Prix Alain-Grandbois or Alain Grandbois Prize is awarded each year to an author for a book of poetry * Rosa 'Alain', popular red floribunda rose variety See also * Allain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
