Querying Business Processes with BP-QL

1
Querying Business Processes with BP-QL

• Catriel Beeri Hebrew University
• Anat Eyal,
• Simon Kamenkovich, Tel Aviv University
• Tova Milo

2
Business Processes

• Complex applications
• Integrating remote Web Services
• Standards facilitate development
• XML data exchange
• BPEL specifications

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Service Specifications
ltprocessgt lt! Definition and roles of
participants --gt ltpartnerLinksgt ...
lt/partnerLinksgt lt!- Data/state used within the
process --gt ltvariablesgt ... lt/variablesgt lt!-
Exception handling --gt ltfaultHandlersgt ...
lt/faultHandlers lt!- Error recovery undoing
actions --gt ltcompensationHandlersgt ... lt!-
Concurrent events --gt lteventHandlersgt ...
lt/eventHandlersgt lt!- Business process flow --gt
(activities) lt/processgt
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Motivation
Not just simplifying development This is a new
mine of Information!

• Interesting questions
• What kind of credit services are used
  (in)directly?
• How can I buy a plane ticket ?
• Can one get a price quote without giving first
  credit card info?

• Design Considerations
• A dedicated language vs. XQuery
• Visual query similar to specifications (BPEL
  designer)
• Query specifications vs. execution flow
• Distributed query processing

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Query Language
Which operations are provided by the Airline
service?

• Query language extensions (1)
• Transitive edge
• Zoom-in node
• Local/ global

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Query with Negation
Which airline services allow to search without
login first?

• Query language extensions (2)
• Negation

We can also query the data flow (not just the
execution flow)
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Architecture

• Active XML
• XML with embedded calls to Web Services

• The problem
• Distribution of specifications
• Cycles in the service graph

BP-QL
Query Editor
Result Viewer
BPQL 2 XOQL
Post Processor
AXML peer S1
AXML peer S2
query
Query processor
Evaluator
SOAP
AXML
read update
SOAP wrapper
read update
consults
AXML
AXML peer S3
service descriptions
SOAP
AXML document store