Getting Startedwith pureQuery

Chapter 15 – pureQuery and pureXML 293
15.5 Summary
This chapter proposed three approaches for handling pureXML data in pureQuery
applications. These approaches highlight the usage of different layers of an application to
do the required step of XMLJava mapping. There are certainly other alternative
approaches, and the ones listed can be combined in order to provide customized solutions.
Each one of the approaches has it advantages and disadvantages that you should
consider when developing your pureQuery application that uses pureXML data:
• Giving control to the SQL layer
o
o
Pros: it takes advantage of pureQuery relational mapping facilities.
Reduced I/O, as only required info flows from database to application.
Cons: requirement changes manifest in updates to both the SQL/XML
statement and the bean. SQL/XML statement can become too complex
depending on the amount of information fetched from XML data.
• Giving control to the data access API
o
o
Pros: Application and SQL layer are oblivious to schema changes. Tooling
streamlines adoption of new schema or change in requirements.
Cons: beans hierarchy can become overly complex when mapping from
large XSD schemas. Increased I/O, as the whole document is fetched from
database into data access layer.
• Giving control to the application layer
o
o
Pros: schema and requirement changes are oblivious to data access API
and SQL layer. Flexibility when multiple requirements coexist.
Cons: mapping complex to implement. Increased I/O, as full document
contents are sent from database to application and back.
This chapter is a shorter version of the IBM developerWorks article “Handling pureXML
data in Java applications with pureQuery”, available at:
http://www.ibm.com/developerworks/data/library/techarticle/dm-0901rodrigues/index.html