an xml enablement of db2 - db2 xml extender.pdf

8/9/2019 An XML Enablement of DB2 - DB2 XML extender.pdf

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NET.OBJETDAYS 2000October 10-12, 2000Xu and Cheng, Pler

An XML Enablement of DB2

-- DB2 XML Extender

Jane Xu and Josephine Cheng

Database Technology Institute,

Silicon Valley Lab, IBM

[email protected]

Manfred Pler

IBM Datamanagement

[email protected]

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Agenda

XML and DB2

XML Extender Overview

Storage and Access of XML DocumentsXML Processing of Relational Data

Other Features

Conclusions

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XML and DB2

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XML brings data to the web, completing thenecessary components for 90%+ of

e-business applications.

Universal Communication - Internet

Universal User Interface - Browsers

Universal Programming - Java

and now...

Universal Information - XML

XML completes the puzzle

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Putting DB2's Power to Support XML

DB2 provides stability, scalability, and security

Your mission-critical business data is currently

stored in DB2DB2's XML support adds its power to enable yourbusiness data for XML

With DB2's XML support, you can makeapplications to:

Store XML documents for fast search

Compose or decompose XML documents from or

into relational tablesQuery XML data based on XPath expressions

You can build B2B and B2C applications on topof DB2 using XML Extender as the SDK

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DB2

XML

DOC

DB2 XML

Extender

File System

XML

FilesDAD

(Data Access

Definition)

Application

Program

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Two Access and Storage Methods

DB2 XML

Extender

DAD(Data Access

Definition)

DB2 UDB

Application

XMLColumn

book

user table

XMLCollection

XML

DOC

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Storedprocedures

UDFs

Admin

GUI

AdminCommand

DB2

CAE

Client

XMLParser

Utilities

XML ExtenderServer

XML ExtenderClient

DB2

Server

Server

XML Extender Components

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DAD:Data Access Definition

XML document itself

Define the mapping between XML document and

relational tablesUsed for both XML Column and XML Collection

XPath Standard:

XPath:

part of the XSLT, as W3C recommendation

A subset of the abbreviated location paths is usedto identify XML element or attribute

The data model is used in XML collection mapping.

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Storage and Access of XML

Documents

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UDT (DB2 User Defined Type):

XMLFile - external file name

XMLVarchar - for internal short document

XMLCLOB - for internal long documentUDF (DB2 User Defined Function):

Import/Storage

Retrieval

Update

Extract:

Extract XML element/attribute values fromdocuments

Convert characters in XML documents into generalSQL data types

Provide both scalar and table UDFs for each datatype

XML Column Storage and Access

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Select

db2xml.extractDouble(order,'/Order/Part/ExtendedPrice')from order_tab where invoice_number = 356

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Thompson .... ....

DAD

(Data Access

Definition)

part_tab

part_key ....

82 ....

order_tab

order_key customer

99 Thompson

83 ....

Order

(XMLCLOB)... ...

... ...

Sales_tabside tables

Using Side Tables for Fast Searches inXML Documents

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Use Text Extender on Structural TextSearch

XML column or decomposed column in tables can beenabled with Text Extender

Use Text Extender section support of structural textsearch in query

Example:

SELECT order FROM sales_tableWHERE CONTAINS(orderHandle,'MODEL order SECTION(/Order/Customer)"John Doe" ') = 1

No dependency on Text Extender if searching on SQLdata types of XML element/attribute values is sufficient

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XML Processing of

Relational Data

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Document/Database Mapping with DAD

Thompson .... ....

part_tab

part_key ....

82 ....

order_tab

order_key customer

99 Thompson

DAD

(Data Access

Definition)

83 ....

order_key

99

99

Mapping Methods:SQL (compostion only)

RDB_node (XML-Style for

compostion/decomposition)

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Two Mapping Schemes

SQL mapping (composition only)

SQL syntax

specify the SQL select statementspecify the mapping between column and XML datain attribute_node and text_node

certain restrictions apply

RDB_node mapping (comp. & decomp.)XML syntax

specify tables and relationship among tables in theRDB_node of the root element_node

specify RDB_node with table name, column nameand optional condition for attribute_node andtext_node

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Dynamic Mapping

Ability to take DAD to generate or shred XMLdocuments, where DAD can be created byapplications on the fly.

Change query criteria by overriding query condition

for document generationSQL_OVERRIDE:

replace the SQL query

change conditions in the WHERE clause

designed for DBMS experts

XML_OVERRIDE:

Use XPath syntax to define element or attribute,

Specify the constraints on XML elements orattributes on the documents to be generated

An example:

/department/@id = 'E01' AND

/department/name = 'John Duo'

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Use Stored Procedures to ProcessXML Collections

Decompose XML documents into new or existingtables

Compose XML documents from existing data ordecomposed XML documents

Specify override type and value for dynamicmapping

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Other Features

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Other Features

DTD Repository

Store your DTDs in DB2

One DTD can be referenced by many XML

documents and more than one XML column andXML collection.

Use DTDID to validate input XML documents atthe insertion time

Validating Input or Generated XML DocumentsValidation can be specified in your DAD,

Supported in both XML Column and Collectionfeatures

GUI based Administration Tool

Help enabling your database, tables, columns,and collections for XML

Help creating DADs

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Conclusions

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U i F t f DB2 XML E t d


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Unique Features of DB2 XML Extender

In XML ColumnXPath based queries on individual documentsusing extracting UDFs

Use XPath data model to map XML structure to

relational tablesXPath based element/attribute update

Providing Sequence number to identify multipleoccurred XML document element or attribute

In XML CollectionDirect mapping from relational to your target XMLdocument structure, for high volume B2Bapplications

Dynamically generate XML documents from DB2data, and change query criteria via overridingquery conditions

Decompose XML documents and storing

un-tagged data into DB2 tables

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Validate input or generated XML documents againstDTDs

Integrated with DB2 Net.Data for Web applicationsWrite your applications with the interface ofembedded SQL, ODBC, JDBC, or SQLJ

Integrate XML technology with traditional relational

dataIntegrated with DB2 UDB package

For Your e-business Applications

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