Reference: Fikes, R.; Hayes, P.; & Horrocks, I. DQL - A Query Language for the Semantic Web. Knowledge Systems Laboratory, 2002.
Abstract: DQL is a language and protocol supporting agent to agent query-answering dialogues using knowledge represented in DAML+OIL/OWL. DQL is a formal language and precisely specifies the semantic relationships among a query, a query answer, and the knowledge base(s) used to produce the answer. Unlike standard database and Web query languages, DQL supports query-answering dialogues in which the answering agent may use automated reasoning methods to derive answers to queries, as well as dialogues in which the knowledge to be used in answering a query may be in multiple knowledge bases on the Semantic Web, and/or where those knowledge bases are not specified by the querying agent. In this setting, the set of answers to a query may be of unpredictable size and may require an unpredictable amount of time to compute. DQL therefore allows querying agents to specify the maximum number of answers required, and answering agents to return answers as they are determined and to continue obtaining additional answers only as requested.
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