Object XML Mappings

Object XML MappingsAn introduction

Joost [email protected]

Friday, February 27, 2009

mailto:[email protected]

mailto:[email protected]

1. Introduction to ORM’s in the SQL world!

2. Object XML Mappings


Enterprise Application Layers

Presentation Interaction

Domain Logic

Data Source Storage


Enterprise Application Layers

Presentation Interaction

Domain Logic

Data Source Storage

ORM’s live here!


Object Relational Mapping

Joost Diepenmaat 26

Jan Klaassen 24

John Doe 23

firstname lastname age



Joost Diepenmaat 26

Jan Klaassen 24

John Doe 23

firstname lastname age Class Student

firstnamelastnameage



Joost Diepenmaat 26

Jan Klaassen 24

John Doe 23

firstname lastname age Class Student

firstnamelastnameage


ORM & ActiveRecord

"An object that wraps a row in a database table or view, encapsulates

the database access, and adds domain logic on that data."

- Martin Fowler


Very short demo...


More ORM!


class Student < ActiveRecord::Base has_many :courses belongs_to :universityend

student = Student.find_by_name("Joost")student.courses #returns all courses

Associations


class Student < ActiveRecord::Base validates_presence_of :firstname, :lastname validates_uniqueness_of :number validates_acceptance_of :terms_of_service validates_confirmation_of :passwordend

Validations


✓Associations

✓Validations

✓Finders

✓Callbacks

✓Observers

✓Inheritance

✓Direct manipulation

✓Transactions

✓Database abstraction

✓etc. etc.


• Java: Hibernate

• Ruby: ActiveRecord, DataMapper

• .Net: LINQ

• Python: Django’s ORM

• More, more, more....

ORM’s are popular


ORM’s are SQL based.


Complex XML standards

• OpenXML

• GIS

• Universal Business Language

• ebXML

• XBRL

• Healthcare XML

• Voice XML


ORM’s do not support native XML storage.


2. Object Relational XML Mappings


Place XML in domain logic

into separate classes.


<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>...




Class Student




Class Student

Class Course




Class Student

Class Course

student = Student.find_by_name("Joost")student.courses


Thesis studies:

The possibilities of an OXM with XML/XPath as

a base language for storage.


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?


Object

Elements map

Pathfinder core

SQL storage

Student

tag “<student>”

XPath to SQL queries

pre | size | level

layer contains


Elements MapUniversity

Pathfinder

SQL

ElementsRegister

ObjectMapping

ElementsMap

XPathQueries Etc.

Student CourseObjects


Questions?


Object XML Mappings

Technology