Database Theory in Action: From Inexpressibility to Efficiency in GQL's Order-Constrained Paths

Abstract: Pattern matching of core GQL, the new ISO standard for querying property graphs, cannot check whether edge values are increasing along a path, as established in recent work. We present a construc- tive translation that overcomes this limitation by compiling the increasing-edges condition into the input graph. Remarkably, the benefit of this construction goes beyond restoring expressiveness. In our proof-of-concept implementation in Neo4j's Cypher, where such path constraints are expressible but costly, our compiled version runs faster and avoids timeouts. This illustrates how a theoretically motivated translation can not only close an expressiveness gap but also bring practical performance gains.