ECTree: an extended tree index for attributed subgraph queries

Graphs are popular data structures for modeling complex data types. There is a need for managing such graph data and providing efficient querying tools. In the graph mining realm, the problem lies in indexing a large number of graphs for fast retrieval. Indexing attributed graphs and using attributed queries can provide faster response time and results that are more refined. Our index technique ECTree focuses on extending an existing index to support attributed graph indexing and providing subgraph querying access to the extended index. The aim is to find a way such that the labels of the graphs as well as the attributes of the graphs are indexed at the same time. A query format is provided to query the extended index with flexibility on the attributes. In addition, regular expressions are used as query labels to provide flexibility. We also introduce a label-irrelevant vertex degree-attribute pruning method. All the techniques presented in our work are validated through experiments on both real and synthetic datasets.