1. Object XML Mappings
An introduction
Joost Diepenmaat
j.h.b.diepennaat@student.utwente.nl
Friday, February 27, 2009

2. 1. Introduction to ORM’s in
the SQL world!
2. Object XML Mappings
Friday, February 27, 2009

3. Enterprise Application
Layers
Presentation Interaction
Domain Logic
Data Source Storage
Friday, February 27, 2009

4. Enterprise Application
Layers
Presentation Interaction
ORM’s live
Domain Logic
here!
Data Source Storage
Friday, February 27, 2009

5. Object Relational Mapping
firstname lastname age
Joost Diepenmaat 26
Jan Klaassen 24
John Doe 23
Friday, February 27, 2009

6. Object Relational Mapping
firstname lastname age
Class
Student
Joost Diepenmaat 26
firstname
Jan Klaassen 24
lastname
John Doe 23 age
Friday, February 27, 2009

7. Object Relational Mapping
firstname lastname age
Class
Student
Joost Diepenmaat 26
firstname
Jan Klaassen 24
lastname
John Doe 23 age
Friday, February 27, 2009

8. ORM & ActiveRecord
quot;An object that wraps a row in a
database table or view, encapsulates
the database access, and adds
domain logic on that data.quot;
- Martin Fowler
Friday, February 27, 2009

9. Very short demo...
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10. More ORM!
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11. Associations
class Student < ActiveRecord::Base
has_many :courses
belongs_to :university
end
student = Student.find_by_name(quot;Joostquot;)
student.courses #returns all courses
Friday, February 27, 2009

12. Validations
class Student < ActiveRecord::Base
validates_presence_of :firstname, :lastname
validates_uniqueness_of :number
validates_acceptance_of :terms_of_service
validates_confirmation_of :password
end
Friday, February 27, 2009

13. ✓Associations ✓Inheritance
✓ ✓
Validations Direct manipulation
✓Finders ✓Transactions
✓ ✓
Callbacks Database abstraction
✓Observers ✓etc. etc.
Friday, February 27, 2009

14. ORM’s are popular
• Java: Hibernate
• Ruby: ActiveRecord, DataMapper
• .Net: LINQ
• Python: Django’s ORM
• More, more, more....
Friday, February 27, 2009

15. ORM’s are
SQL based.
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16. Complex XML standards
• OpenXML • ebXML
• GIS • XBRL
• Universal • Healthcare XML
Business
• Voice XML
Language
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17. ORM’s do not support
native XML storage.
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18. 2. Object Relational
XML Mappings
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19. Place XML
in domain logic
into separate classes.
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20. <student>
<name>Joost</name>
<courses>
<course>
<title>XML & DB I</title>
<score>7</score>
</course>
<course>
<title>XML & DB II</title>
<score>9</score>
</course>...
Friday, February 27, 2009

21. Student <student>
Class
<name>Joost</name>
<courses>
<course>
<title>XML & DB I</title>
<score>7</score>
</course>
<course>
<title>XML & DB II</title>
<score>9</score>
</course>...
Friday, February 27, 2009

22. Student <student>
Class
<name>Joost</name>
<courses>
Course <course>
Class
<title>XML & DB I</title>
<score>7</score>
</course>
<course>
<title>XML & DB II</title>
<score>9</score>
</course>...
Friday, February 27, 2009

23. Student <student>
Class
<name>Joost</name>
<courses>
Course <course>
Class
<title>XML & DB I</title>
<score>7</score>
</course>
<course>
<title>XML & DB II</title>
<score>9</score>
</course>...
student = Student.find_by_name(quot;Joostquot;)
student.courses
Friday, February 27, 2009

24. Thesis studies:
The possibilities of an OXM
with XML/XPath as
a base language for storage.
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25. Research Questions
1. How can we extend RoR with XPath
Accelerator to create an XML database for
efficient XML storage and XPath processing?
2. How can we implement XML based Object
Mapping on the XML database created?
3. What kind of XML related functionality can
we add to the system?
Friday, February 27, 2009

26. layer contains
Object Student
Elements map tag “<student>”
Pathfinder core XPath to SQL queries
SQL storage pre | size | level
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27. Elements Map
University Student Course
Objects
Object
Elements XPath
Elements
Etc.
Mapping
Map
Register Queries
Pathfinder
SQL
Friday, February 27, 2009

28. Questions?
Friday, February 27, 2009