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Solving equations in the relational algebra

Joachim Biskup·Jan Paredaens·Thomas Schwentick·Jan Van den Bussche
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Abstract

Enumerating all solutions of a relational algebra equation is a natural and powerful operation which, when added as a query language primitive to the nested relational algebra, yields a query language for nested relational databases, equivalent to the well-known powerset algebra. We study \emph{sparse} equations, which are equations with at most polynomially many solutions. We look at their complexity, and compare their expressive power with that of similar notions in the powerset algebra.

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Joachim Biskup, Jan Paredaens, Thomas Schwentick, Jan Van den Bussche. 2003-12-10. Solving equations in the relational algebra. https://arxiv.org/abs/cs/0106034

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