What Went On at QL'98

March 2, 1999

Lisa Rein

What Went On at QL'98

QL'98, the W3C Workshop on Query Languages, brought together over 92 participants from 31 different commercial companies, 7 different research facilities, and 19 academic institutions to discuss what could be done to standardize a query language that understood XML documents in the way that SQL understands a relational database.  Reports from numerous participants agree that the workshop activities provided a useful education for its attendees, helping them to understand the many different approaches to solving this problem.

Although only about 50 participants were expected, the response was so great that the W3C had to invoke rules to limit participation to two people for each member company and one for each invited organization. "If the workshop would have been "open call", I think we could have had a really amazing number of participants," explained QL'98 chair, Massimo Marchiori.

"It's been an amazing workshop, for the variety of people attending, the number of incredibly high-quality contributions, and the deep lively discussions," explained Marchiori. One goal of the workshop was to solicit input on whether the W3C should start a new working group to define an XML-based query language. Another goal was to clarify the needs in this area of different W3C working groups like XML, RDF, P3P, XSL, Math, and DOM.  Its organizers also wanted to understand the related needs of commercial database companies as well as those whose business relies on query technologies.

"There were many high-quality presentations, coming from very distinct positions," explained XQL co-editor Jonathan Robie (Texcel Research). "Some proposals focused on querying individual documents; others focused on querying repositories or indexed collections. Some proposals focused on documents; others on data taken from sources such as databases."

According to Robie, some of the proposals were more closely based on XML than others. Some suggested using RDF graphs or semi-structured database models. Most proposals suggested a query language, although a few others proposed that full-fledged query protocols (such as the Z39.50 information retrieval protocol) were needed in order to negotiate the details of query processing among clients and servers in a fully distributed, heterogeneous environment.

"It was an amazingly diverse group," remembers IBM's Paul Cotton. "Diverse in the way that each group approached the question the W3C had proposed, as well as diverse in the solutions that each group proposed. After a while, we realized that we were sometimes talking about different data models, and that before we could go any further, we'd have to agree on just what that XML data model was."

A total of 66 position papers were submitted to the workshop (position papers were required for attendance). Many of the papers commented directly on one or more of the other proposals. Although some position papers were rather lengthy (such as Microsoft's Adam Bosworth's), most were only one or two pages. Still others, such as Quark, Inc., submitted a non-position paper explaining just how simple their requirements were.

Others have been pursuing related work as part of RDF or the Dublin Core activities or the Z39.50 information retrieval protocol developed for the library community. Representatives from these communities came to the workshop to help educate other groups about their requirements.

So what were the issues everyone talked about?