Query with Assumptions for Probabilistic Relational Databases
Caicai Zhang, Zhuolin Mei, Bin Wu, Zhiqiang Zhao, Jing Yu, Wang, Qingqing · Tehnicki vjesnik - Technical Gazette · 2020
Users may have prior knowledge about a probabilistic database.They prefer to query over a probabilistic database on their prior knowledge which cannot be written as component clauses of conventional SQL queries.A naive approach is to query over a new database version, which is generated by transforming the original probabilistic database to satisfy users' prior knowledge; however, it is impractical to generate a different probabilistic database version for each prior knowledge.In this paper, we propose the concept of the query with assumptions which allow users to describe their prior knowledge with a newly introduced ASSUMPTION clause of SQL.We also propose an approach to obtain the result of a query based on assumption clauses.The experimental studies show our approach has better performance compared to the naive approach.