Z39'50 and W3C XML QL

1
Z39.50 and W3C XML QL

• Mark Needleman
• Data Research Associates, Inc
• ZIG Meeting
• December 2000

2
XML QL

• Query Language Only
• Formal Data Model and Algebra
• May Have multiple syntaxes - but 1 language
• Protocol Independent
• May embed some of the functionality of Z39.50
  directly into the language

3
Z39.50

• More than just a Query Language - a protocol with
  supporting infrastructure
• Z39.50 model supports multiple types of queries
• Provides session management
• Provides result set management
• Provides supporting information retrieval
  functionality beyond the query

4
XML Ql vs Z39.50

• QL - XML based (at least one syntax)
• Z39.50 ASN.1/BER based
• QL - Protocol Independent
• Z39.50 - Very much protocol dependent
• QL - all functionality provided for and expressed
  in the query language
• Z39.50- provides supporting information retrieval
  functionality beyond the query
• QL - A De facto standard?
• Z39.50 - An official standard

5
Possible Futures

• Add QL as one more Query type in Z39.50?
• Abandon Z39.50 and just use functionality and
  model provided by QL?
• Some combination of the two?

6
Z39.50 in the Future?

• Retain concepts and model of information
  retrieval provided by current protocol expressed
  using XML QL but run over a more modern transport
  like HTTP and/or XML Protocol