Querying Sensor Networks with Extended SQL

A wireless sensor network can be modeled as a database with unique features like dynamic, and approximate, unreliable. Query languages used in traditional databases for data and information retrieval thus need to be extended to support the retrieval of data and information from such a sensor network database. This paper presents extensions to existing query language, in particular SQL, to be used in sensor networks. We propose four query extensions, including timing, aggregations, QoS, and semantics. Syntax and examples are presented to explain the extensions. Practical issues are discussed on how to incorporate the extensions into a sensor network.