This article shows how the adapter developed by the iClass project (iClass Consortium, 2004) takes advantages of SQI independence in terms of query language and resulting formats to resolve learning object locations (i.
Finally, the section "Obtaining Learning Objects with SQI" describes how SQI can be enriched by a new query language and a new result format to request learning object location without modifying the interface itself.
Considering two repositories sharing at least a common query language and a common metadata format, the following steps are necessary to enable one repository (referred as the source of the query) to query the other (referred as the target of the query) using SQI:
the source sends a query in the selected query language,
The query management methods permit the configuration of query parameters such as the query language (setQueryLanguage), the format of the results (setResultsFormat), the maximum number of results returned (setMaxQueryResults), and the duration of a query (setMaxDuration).
The simplicity of SQI, its ability to be used in combination with any query language and result format, and its asynchronous query mode make it a good candidate interface for searching metadata in a peer-to-peer network of metadata repositories such as the iClass content server (6).
The legacy system calls the adapter to indicate that it will use a new query language (setQueryLanguage) and a new result format (setResultsFormat) to request a learning object location.
The SPARQL specification defines a query language and a protocol and works with the other core Semantic Web technologies from W3C: Resource Description Framework (RDF) for representing data; RDF Schema; Web Ontology Language (OWL) for building vocabularies; and Gleaning Resource Descriptions from Dialects of Languages (GRDDL), for automatically extracting Semantic Web data from documents.
W3C RDF Data Access Working Group produced the three SPARQL Recommendations issued today: the SPARQL Query Language for RDF, The SPARQL Protocol for RDF, and the SPARQL Query Results XML Format.