04-19-2001 1

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

MQP Advisor:Prof. Elke A. Rundensteiner, PhD

Sponsor:Verizon Laboratories Incorporated

MQP Project Members:MQP Project Members:

Tien Vu, Tien Vu,

Mirek Cymer, Mirek Cymer,

John LeeJohn Lee

04-19-2001 2

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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XMLXMLDataData

SubSubsystemsystem

LegendLegend

Traditional System Architecture

XMLXML

XMLXMLQueryQuery

XMLXMLUserUser

XML Query EngineXML Query Engine

XML ManagerXML Manager

RDBMS

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Motivation for Flexible Mapping

CarCar

MakeMake

ModelModel

YearYear

car

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

SELECT * FROM model;SELECT * FROM model;

SELECT model FROM car WHERE make = ‘Ford’;SELECT model FROM car WHERE make = ‘Ford’;

iid pid

1 0

… …

iid pid Value

2 1 Ford

… … …

iid pid Value

3 1 Mustang

… … … iid pid Value

3 1 2001

… … …

iid pid Make Model Year

1 0 Ford Mustang 2001

… … … … …

04-19-2001 6

XMLXMLDataData

SubSubsystemsystem

LegendLegend

Rainbow Architecture

XMLXML

XMLXMLQueryQuery

XMLXMLUserUser

XML Query EngineXML Query Engine

XML ManagerXML Manager

RDBMS

DTDDTD

DTD ManagerDTD Manager

Restructuring SubsystemRestructuring Subsystem

Flexible mapping = fixed Mapping + restructuringFlexible mapping = fixed Mapping + restructuring

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Rainbow Restructuring Subsystem

DTDDTD XMLXML

DTD ManagerDTD Manager XML ManagerXML Manager

SubSubsystemsystem

DataData

ProcessProcess

LegendLegend

XMLXMLQueryQuery

XMLXMLUserUser

XML Query EngineXML Query Engine

Restructuring SubsystemRestructuring Subsystem

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Rainbow Restructuring Subsystem

DTD XML

DTD Manager XML Manager

SubSubsystemsystem

DataData

ProcessProcess

LegendLegend

Res

truc

turi

ngR

estr

uctu

ring

Mapping

RestructureOperatorLibrary

RestructurerRestructurer

XMLQuery

XMLUser

XML Query Engine

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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

A

B

A

B

x

x

DTD Modifications:DTD Modifications:

Data Changes:Data Changes:

CREATE VIEW out.$A ASCREATE VIEW out.$A AS

SELECT p.SELECT p.<all_columns>, c.$x, c.$x

FROM in.$A p, in.$B cFROM in.$A p, in.$B c

WHERE c.pid = p.iidWHERE c.pid = p.iid

CREATE VIEW out.$B ASCREATE VIEW out.$B AS

SELECT SELECT <all-columns-but-x>

FROM in.$BFROM in.$BPushup

In Out

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Instantiated Pushup Operator

Car

Model

Value

DTD Modifications:DTD Modifications:

Data Changes:Data Changes:

CREATE VIEW out.Car ASCREATE VIEW out.Car AS

SELECT p.iid, p.pid, c.valueSELECT p.iid, p.pid, c.value

FROM in.Car p, in.Model cFROM in.Car p, in.Model c

WHERE c.pid = p.iidWHERE c.pid = p.iid

CREATE VIEW out.Model ASCREATE VIEW out.Model AS

SELECT iid, pidSELECT iid, pid

FROM in.ModelFROM in.Model

Pushup

Car

ModelValue

In Out

pushUpAttribute(‘Model’, ‘Value’, ‘Car’, ‘Model’);

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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’);

CarCar

ModelModel

iid pid

1 0

… …

iid pid Value

3 1 Mustang

… … …

2

car

…

Mustang

Model

…

0

pid

…

1

iid1

car

…

Mustang

Value

…

0

pid

…

1

iid

ModelModel

…

1

pid

…

3

iid

04-19-2001 13

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

New39%

Reused18%

Extended43%

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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 IBM’s

XML-Generator

DTD CONTENT:DTD CONTENT:

<!ELEMENT one (two+)><!ELEMENT one (two+)>

<!ELEMENT two (three)><!ELEMENT two (three)>

<!ELEMENT three (four)><!ELEMENT three (four)>

<!ELEMENT four (five)><!ELEMENT four (five)>

<!ELEMENT five (six)><!ELEMENT five (six)>

<!ELEMENT six (seven)><!ELEMENT six (seven)>

<!ELEMENT seven EMPTY><!ELEMENT seven EMPTY>

<!ATTLIST seven attribute #REQUIRED><!ATTLIST seven attribute #REQUIRED>

04-19-2001 18

Query Performance Evaluation

Time of Join Query (data-size=22Mb)

0

10

20

30

40

0 1 2 3 4 5 6 7

# of PushUpAttribute

Que

ry T

ime

(s)

Time of Join Query

04-19-2001 19

Overhead Cost

Time of overhead (datasize=22Mb)

050

100150200250300350

0 1 2 3 4 5 6 7

# of pushUpAttribute

Res

truct

ure

Tim

e (s

)

overhead time

04-19-2001 20

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

04-19-2001 21

Potential Future Work

XML query translation to SQL Experiment with test plans and test beds to realize

the full potential of the restructuring component.

04-19-2001 22

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