“…UML and ER diagrams are other examples. There has been a considerable effort, from both database and data mining communities, in developing techniques for managing, processing, and analyzing graph databases, including graph pattern discovery [12,15,18,22], structurebased graph queries [5,6,10,11,19,23,27,26], etc. The substructure search problem, also called subgraph containment query, is that for a graph database and a given query graph, we want to find all data graphs which contain the query graph.…”