RankSQL: Query Algebra and Optimization for Relational Top-k Queries

This paper introduces RankSQL, a system that provides a systematic and principled framework to support efficient evaluations of ranking (top-k) queries in relational database systems (RDBMS), by extending relational algebra and query optimization. Previously, top-k query processing is studied in the middleware scenario or in RDBMS in a "piecemeal" fashion, i.e., focusing on specific operator or sitting outside the core of query engines. In contrast, we aim to support ranking as a first-class database construct. As a key insight, the new ranking relationship can be viewed as another logical property of data, parallel to the "membership" property of relational data model. While membership is essentially supported in RDBMS, the same support for ranking is clearly lacking. We address the fundamental integration of ranking in RDBMS in a way similar to how membership, i.e., Boolean filtering, is supported. We extend relational algebra by proposing a rank-relational model...

• Type: Conference
• Year: 2005
• Where: SIGMOD
• Authors: Chengkai Li, Kevin Chen-Chuan Chang, Ihab F. Ilyas, Sumin Song
• Keywords: Database, Fundamental Ranking Principle, Ranking Property, Ranking Query Plans, SIGMOD 2005