Contextual Query Language
The Common Query Language ( CQL ) is a formal language to requests for information systems such as, for example, to construct library catalogs.
- Powerful query languages that are difficult to learn and cope with (eg SQL).
- Simple and intuitive query languages that are less powerful, however (eg, Google 's query language ).
The goal of CQL is to achieve a combination of simplicity and performance. This very simple queries are possible, which can be expanded in complex query constructs when needed. In the design decision was made to develop a simple human-readable query language in the foreground. This concept is similar to the basic idea of XML.
Currently, CQL is available in version 1.1 of 13 February 2004. Version 1.2 has been renamed Contextual Query Language.
Encoding in XML
CQL expressions can be expressed in XML, the resulting language is called XCQL.
- Common Query Language page of the Library of Congress.
- CQL portal to more information and free implementations for various programming languages
- Description Language