Active XQuery                  
 
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Active XQuery is an extension of XQuery to declaratively define reactions to data changes, in the same spirit as triggers in SQL. We envision two main applicative domains for XML triggers:

  • XML data integrity - we propose to exploit Active XQuery and the ECA paradigm so as to maintain data integrity w.r.t. arbitrarily complex constraints - i.e. not only those type and cardinality constraints, that are natively defined within XML Schema, but also arbitrary constraints which can be formulated by means of XQuery expressions (and possibly be embedded into XML Schema definition, so as to play the same role assertions play into the relational framework)
  • Data Flow Analysis - the ECA paradigm can also be applied to monitoring the flow of data in a channel which is used as a communication means by two applications (which is quite on fashion at present, due to the widespread use and ever-increasing popularity of Web Services)

Papers:
ICDE 2002 (.PDF 142 KB)