Enhancing Search with Structure

Keyword search has traditionally focussed on retrieving documents in ranked order, given simple keyword queries. Similarly, work on keyword queries on structured data has focussed on retrieving closely connected pieces of data that together contain given query keywords. In recent years, there has been a good deal of work that attempts to go beyond the above paradigms, to improve search experience on unstructured textual data as well as on structured or semi-structured data. In this paper, we survey recent work on adding structure to keyword search, which can be categorized on three axes: (a) adding structure to unstructured data, (b) adding structure to answers, and (c) adding structure to queries allowing more power than simple keyword queries, but while avoiding the complexity of elaborate query languages that demand extensive schema knowledge.