Rainbow - Bridging XML and Relational Databases: Design, Implementation, and Evaluation

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Rainbow - Bridging XML and Relational Databases
Design, Implementation, and Evaluation

• MQP Advisor
• Prof. Elke A. Rundensteiner, PhD
• Sponsor
• Verizon Laboratories Incorporated

MQP Project Members Tien Vu, Mirek Cymer, John
Lee
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HTML vs. XML
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XML Data Management by RDBMS

• Microsoft, IBM, Informix, Oracle,...
• Advantages
• Matured database tools available.
• Efficient query and analysis tools.
• Easy integration with existing business
  databases.
• Issues
• Map between XML and Relational Model.
• Update Propagation.
• Query Translation and Optimization.

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Traditional System Architecture
XMLQuery
XML
User
Legend
RDBMS
XML Query Engine
XML Data
Subsystem
XML Manager
XML
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Motivation for Flexible Mapping

• Query Performance varies with respect to how
  data is mapped.

Car
SELECT FROM model
iid pid
1 0

Make
SELECT model FROM car WHERE make Ford
iid pid Value
2 1 Ford

car
iid pid Make Model Year
1 0 Ford Mustang 2001

Model
iid pid Value
3 1 Mustang

Year
iid pid Value
3 1 2001

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Rainbow Architecture
XMLQuery
XML
User
Legend
RDBMS
XML Query Engine
XML Data
Subsystem
XML Manager
XML
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Rainbow Restructuring Subsystem
XMLQuery
XML
User
Legend
XML Query Engine
Subsystem
Data
Restructuring Subsystem
Process
DTD Manager
XML Manager
DTD
XML
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Rainbow Restructuring Subsystem
XMLQuery
XML
User
Legend
XML Query Engine
Subsystem
Data
Process
DTD Manager
XML Manager
DTD
XML
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Restructuring Operator Library

• Library contains following operators
• Pushup/Pushdown Attribute
• Pushup/Pushdown Nesting
• Rename Item/Rename Attribute
• SwitchNesting
• Split/Merge Nesting
• Reference/Dereference
• Operator is composed of
• DTD Modifications
• Data Changes

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Pushup Attribute Operator
DTD Modifications
Data Changes
In
Out
A
A
CREATE VIEW out.A AS SELECT p.ltall_columnsgt,
c.x FROM in.A p, in.B c WHERE c.pid p.iid
B
B
x
x
CREATE VIEW out.B AS SELECT ltall-columns-but-xgt F
ROM in.B
Pushup
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Instantiated Pushup Operator
DTD Modifications
In
Out
Car
Car
Data Changes
CREATE VIEW out.Car AS SELECT p.iid, p.pid,
c.value FROM in.Car p, in.Model c WHERE c.pid
p.iid
Model
Model
Value
CREATE VIEW out.Model AS SELECT iid, pid FROM
in.Model
Value
pushUpAttribute(Model, Value, Car, Model)
Pushup
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Mapping

• Mapping is a Sequence of Instantiated Operators
• For Example

1. pushUpAttribute(Model, Value, Car,
Model) 2. renameAttribute(Car, Value,
Model)
Car
iid pid
1 0

Model
iid pid Value
3 1 Mustang

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Rainbow Implementation

• Development Tools
• Java Visual Café 4, Javadoc, JAVA2
• Oracle 8i, XML 4J, JDBC1.2, SQL
• Statistics of Class Implementation
• 44 total
• 17 created
• 19 extended
• 8 reused

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Screen Shot of Rainbow
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Screen Shot of Rainbow
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Screen Shot of Rainbow
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Setup for Rainbow Evaluation

• Experimental
• Database Server
• Oracle 8i on a PII 300MHz, 256MB, Microsoft NT
  Server
• Client
• Pentium 233MHz, 128MB, Microsoft NT Workstation
• Data
• Designed a DTD
• Generated XML using IBMs XML-Generator

DTD CONTENT lt!ELEMENT one (two)gt lt!ELEMENT
two (three)gt lt!ELEMENT three (four)gt lt!ELEMENT
four (five)gt lt!ELEMENT five (six)gt lt!ELEMENT six
(seven)gt lt!ELEMENT seven EMPTYgt lt!ATTLIST seven
attribute REQUIREDgt
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Query Performance Evaluation
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Overhead Cost
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MQP Accomplishments

• Technical accomplishments
• Implemented functional prototype system
• Confirmed feasibility of Rainbow architecture
• Designed automated test bed
• Conducted preliminary experimental studies
• Knowledge acquired
• OO, Java, JDBC, SQL, RDBMS, XML, DTD
• Logistics of setting up experiments
• Teamwork S/W Engineering Software Reuse

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Potential Future Work

• XML query translation to SQL
• Experiment with test plans and test beds to
  realize the full potential of the restructuring
  component.

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• Special thanks to
• Prof. Elke A. Rundensteiner Ph.D. Xin Zhang
• Visit Rainbow at http//davis.wpi.edu/dsrg/TJM/
• Project Members
• Tien Vu, Mirek Cymer, John Lee