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. In DRC, queries have the form: {\langle X1, X2, .... , Xn\rangle | p(\langle X1, X2, .... , Xn\rangle) } </math> where each Xi is either a domain variable or constant, and p(<X1, X2, .... , Xn>) denotes a DRC formula.

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  • 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. In DRC, queries have the form: {\langle X1, X2, .... , Xn\rangle | p(\langle X1, X2, .... , Xn\rangle) } </math> where each Xi is either a domain variable or constant, and p(<X1, X2, .... , Xn>) denotes a DRC formula. The result of the query is the set of tuples Xi to Xn which makes the DRC formula true. This language uses the same operators as tuple calculus, the logical connectives ∧ (and), ∨ (or) and ¬ (not). The existential quantifier (&exist) and the universal quantifier (&forall) can be used to bind the variables. Its computational expresivity is equivalent to that of Relational algebra.
  • 在计算机科学中，域关系演算(DRC)是 Michel Lacroix 和 Alain Pirotte 为关系数据模型介入的作为声明性数据库查询语言。 在 DRC 中，“查询”有如下形式: <math> {<X1, X2, .... , Xn> | p(<X1, X2, .... , Xn>) } </math> 这里的 Xi 要么是一个域变量要么是一个常量，而 p(<X1, X2, .... , Xn>) 指示一个 DRC “公式”。 查询的结果为使得这个 DRC 为真的元组 Xi 到 Xn 的集合。 这个语言使用同域演算一样的算子：逻辑算子 ∧(与)、∨(或)和 ¬(非)。可以用存在量词(&exist)和全称量词(&forall)来绑定变量。 它的计算表达力等价于关系代数。
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  • 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. In DRC, queries have the form: {\langle X1, X2, .... , Xn\rangle | p(\langle X1, X2, .... , Xn\rangle) } </math> where each Xi is either a domain variable or constant, and p(<X1, X2, .... , Xn>) denotes a DRC formula.
  • 在计算机科学中，域关系演算(DRC)是 Michel Lacroix 和 Alain Pirotte 为关系数据模型介入的作为声明性数据库查询语言。 在 DRC 中，“查询”有如下形式: <math> {<X1, X2, .... , Xn> | p(<X1, X2, .... , Xn>) } </math> 这里的 Xi 要么是一个域变量要么是一个常量，而 p(<X1, X2, ....
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  • Domain relational calculus
  • 域关系演算
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