Similarity Search in XML Data using Cost-Based Query Transformations.
Torsten Schlieder · 2001
XML query engines should support structured queries. They should retrieve exact matches as well as results similar to the query. In this paper, we introduce the simple query language approXQL that supports hierarchical, Boolean-connected query patterns. The interpretation of approXQL queries is founded on cost-based query transformations: The total cost of a sequence of transformations measures the similarity between a query and the data and is used to rank the results. All results of an approXQL query can be computed in polynomial time with respect to the database size.