Principled Optimization Frameworks for Query Reformulation of Database Queries
Gautam Das · 2015
Traditional databases have traditionally supported the Boolean retrieval model, where a query returns all tuples that match the selection conditions specified -- no more and no less. Such a query model is often inconvenient for naive users conducting searches that are often exploratory in nature, since the user may not have a complete idea, or a firm opinion of what she may be looking for. This is especially relevant in the context of the Deep Web, which offers a plethora of searchable data sources such as electronic products, transportation choices, apparel, investment options, etc. Users often encounter two types of problems: (a) they may under-specify the items of interest, and find too many items satisfying the given conditions (the many answers problem), or (b) they may over-specify the items of interest, and find no item in the source satisfying all the provided conditions (the empty answer problem).