Query Planning for Searching Inter-dependent Deep-Web Databases

Increasingly, many data sources appear as online databases, hidden behind query forms, thus forming what is referred to as the deep web. It is desirable to have systems that can provide a high-level and simple interface for users to query such data sources, and can automate data retrieval from the deep web. However, such systems need to address the following challenges. First, in most cases, no single database can provide all desired data, and therefore, multiple different databases need to be queried for a given user query. Second, due to the dependencies present between the deep-web databases, certain databases must be queried before others. Third, some database may not be available at certain times because of network or hardware problems, and therefore, the query planning should be capable of dealing with unavailable databases and generating alternative plans when the optimal one is not feasible. This paper considers query planning in the context of a deep-web integration system. We...

• Type: Conference
• Year: 2008
• Where: SSDBM
• Authors: Fan Wang, Gagan Agrawal, Ruoming Jin
• Keywords: Data Sources, Database, Deep Web, Query Planning, SSDBM 2008