Ranking support for keyword search on structured data using relevance models

Keyword query processing over structured data has gained a lot of interest as keywords have proven to be an intuitive mean for accessing complex results in databases. While there is a large body of work that provides different mechanisms for computing keyword search results efficiently, a recent study has shown that the problem of ranking is much neglected. Existing strategies employ heuristics that perform only in ad-hoc experiments but fail to consistently and repeatedly deliver results across different information needs. We provide a principled approach for ranking that focuses on a well-established notion of what constitutes relevant keyword search results. In particular, we adopt relevance-based language models to consider the structure and semantics of keyword search results, and introduce novel strategies for smoothing probabilities in this structured data setting. Using a standardized evaluation framework, we show that our work largely and consistently outperforms all existing systems across datasets and various information needs.