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Search/Retrieve Web Service Version 1.1

SRW/U and CQL Version 1.1 Specifications Released

February 13, 2004.

The SRW Maintenance Agency at the Library of Congress, in conjunction with the SRW Development Group, announces the release of version 1.1 of SRW, the Search/Retrieve Web Service; SRU, Search and Retrieve by URL; and CQL, the Common Query Language.

Version 1.1 supercedes Version 1.0, the initial, experimental version, which was released November 2002. Version 1.1 has been in development for more than a year and is the first official version.

SRW is an XML-based protocol designed to be a low-barrier-to-entry solution for searching and other information retrieval operations across the internet. It uses existing, well tested, and easily available technologies, such as URI, XML, SOAP, HTTP, and XPath. The design reflects the many years of experience gained developing and using Z39.50; SRW is both robust and easy to understand while retaining many of the important aspects of Z39.50. Web technologies reduce the barriers to new information providers allowing them to make their resources available via a standard search and retrieve service. Building on Z39.50 semantics enables the creation of gateways to existing Z39.50 systems.

The protocol may be carried via SOAP or as parameters in a URL. When carried via SOAP, it is referred to as SRW; via URL, as SRU.

CQL is a formal language for representing queries to information retrieval systems, including web indexes, bibliographic catalogues, and museum-collections information. Traditionally, query languages are either (on one hand) powerful and expressive but complex and unfriendly — SQL, Xquery — or (on the other hand) simple and intuitive but neither powerful nor expressive, for example, Google. CQL's goal is to combine the simplicity and friendliness of Google searching with the expressive power of Z39.50, supporting queries ranging from very simple to arbitrarily complex expressions.

Home pages for SRW/U and CQL are and Specifications are linked from these pages and a list of implementers is available.

SRW/U and CQL version 1.1 specifications will be submitted to NISO, the National Information Standards Organization, as NISO Registrations.

The following are among those who have participated in the development of the SRW/U and CQL version 1.1 specification or have otherwise contributed to the intellectual development of SRW/U and CQL (listed alphabetically): Eliot Christian, Ray Denenberg, Adam Dickmeiss, Larry Dixson, Matthew Dovey, Sebastian Hammer, Janifer Gatenby, Poul Henrik Jorgensen, Alan Kent, Ralph LeVan, Bill Moen, Rob Sanderson, Pat Stevens, Mike Taylor, Theo Van Veen.

For information, contact Ray Denenberg, Library of Congress, email

Prepared by Robin Cover for The XML Cover Pages archive. See details in the news story: "US LOC SRW Maintenance Agency Releases Search/Retrieve Web Service Version 1.1." Also earlier news: "ZING Initiative Publishes Search/Retrieve Web Service (SRW) Version 1.0."

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