Sunday, April 11, 2004

Querying Use Cases and Features

Data Access Working Group User Cases: WORKING DRAFT "Because there are no formal standards in these areas, developers in industry and in open source projects have created a wide variety of query languages for RDF data...These languages lack both a common syntax and a common semantics; there is, in fact, a wide variety of semantics: from declartive, SQL-like languages, to path languages, to rule or production-like systems. The existing languages also exhibit a range of extensibility features and builtin capabilities, including inferencing, distributed query, and domain-specific semantics."

Some of the features being considered include: optional triples, disjunction, queries with paths of length two or more edges, able to indicate whether the query response includes entailment from the graph or treats the graph as a fixed object, expressing arbitrary RDF datatypes, queries expressible as a URL, user specifiable query result formats and query results in RDF (closure).

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