Technical Standards for Accessing Information in the 21st Century: Z39.50 to Web Gateways

Libraries have large stake in search protocols because library systems are diverse yet library users need to access multiple sites without learning the search syntax of each site. The purpose of this project is to combine the power of Z39.50 protocol for search and retrieval from heterogeneous systems with the ease of use provided by the Web. The web gateways usually have to make compromise when interfacing Z39.50 protocol. This project reviews and compares the relative advantages of Z39.50 to Web Gateways and several of the newest search protocols and query languages: Search via URL (SRU), OpenSearch, Contextual Query Language (CQL), and XQuery. The models for SRU and OpenSearch operations are described in order to explain differences in functionality − keyword search and simple data record return for OpenSearch and richer search with multiple format data return for SRU. The advantages of CQL are described along with possible complementary uses of the highly detailed and complex XQuery being developed for XML.