2001/06/14 by Jan Van den Bussche, Bussche, Jan Van den, Emmanuel Waller +1
Computer Science · #D.3.3 #Databases (cs.DB) #FOS: Computer and information sciences #H.2.3 #Logic in Computer Science (cs.LO) #cs.DB #cs.LO
paper · pdf · doi:10.48550/arxiv.cs/0106035
arxiv created 2001/06/14 · arxiv updated 2009/11/30
We give a polymorphic account of the relational algebra. We introduce a formalism of ``type formulas'' specifically tuned for relational algebra expressions, and present an algorithm that computes the ``principal'' type for a given expression. The principal type of an expression is a formula that specifies, in a clear and concise manner, all assignments of types (sets of attributes) to relation names, under which a given relational algebra expression is well-typed, as well as the output type that expression will have under each of these assignments. Topics discussed include complexity and polymorphic expressive power.