Concise and Expressive Mappings with +Spicy

We introduce the +Spicy mapping system. The system is based on a number of novel algorithms that contribute to increase the quality and expressiveness of mappings. +Spicy integrates the computation of core solutions in the mapping generation process in a highly efficient way, based on a natural rewriting of the given mappings. This allows for an efficient implementation of core computations using common runtime languages like SQL or XQuery and guarantees very good performances, orders of magnitude better than those of previous algorithms. The rewriting algorithm can be applied both to mappings generated by the system, or to pre-defined mappings provided as part of the input. To do this, the system was enriched with a set of expressive primitives, so that +Spicy is the first mapping system that brings together a sophisticate and expressive mapping generation algorithm with an efficient strategy to compute core solutions.