SQL/XML for Developers - Database Wisdomdatabasewisdom.com/pdf/sqlxml_for_developers_odtug_2009.pdf · SQL/XML for Developers Lewis Cunningham Data Architect, JP Morgan Chase ODTUG

SQL/XML for Developers

Lewis Cunningham Data Architect, JP Morgan Chase http://it.toolbox.com/blogs/oracle-guide http://databasewisdom.com/

ODTUG Kaleidoscope 2009 06/21/2009

http://it.toolbox.com/blogs/oracle-guide




http://databasewisdom.com/


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• Data Architect for JP Morgan Chase

• Twitter: @oracle_ace

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SQL/XML for

Developers

Agenda

What is XML?

What is the XMLType data type?

What is SQL/XML?

What should(n’t) I do with XML?

3

What is XML?

<?XML?>

4

What is XML?

Semi-Structured

Hierarchical

Not relational

Not freeform

Markup “Language”

Tags Identify Data

<NAME>Lewis</NAME>

Human AND machine readable

5

What is XML?

Elements

Root Element

Child Elements

Elements are nodes

Some nodes contain elements

Some nodes contain character data

A node can contain both

Namespaces

6

What is XML?

Well Formed XML

Follows XML formatting rules

All open tags have closing tags

All attribute values are enclosed in quotes

If a document is not well formed, it is not XML

A well formed document may not be a VALID document

Valid XML

Conforms to a specific specification (DTD, XSD, RNG)‏

A valid document will always be a well formed document

7

What is XML?

Simple Example

<rootnode>

<childnode1>Some Data</childnode1>

<childnode2>Some more

<additional>data</additional></childnode2>

<emptytag />

</rootnode>

Element/Tag

Closing

Tag

Childnode1

Child to

rootnode

Empty

Tag

Childnode1 is

Sibling to

childnode2

8

What is XML?

Namespaces

A namespace prevents naming collisions

A namespace provides clarity

A namespace allows multiple documents to be combined

into a single document

9

What is XML?

Simple Example

<rootnode xmlns:abc='http://abc.org/xml' >

<abc:xml:childnode1>Some Data</abc:childnode1>

<abc:childnode2>Some more

<additional>data</additional>

</abc:childnode2>

<emptytag />

</rootnode>

Namespace

Identifier

Namespace

Usage

Namespace

Name

Namespace

URI

Default

Usage

10

What is XML?

Describing XML

DTD – Document Type Description

XSD – XML Schema

Relax NG – REgular LAnguage for Xml Next Generation

11

What is XML?

DTD

A list of valid elements and attributes

May be inline or external

Original descriptive language

Limited and mostly obsolete

No data type definitions

No support for Namespaces

12

DTD Example

<!DOCTYPE note [ <

!ELEMENT note (to,from,heading,body)>

<!ELEMENT to (#PCDATA)>

<!ELEMENT from (#PCDATA)>

<!ELEMENT heading (#PCDATA)>

<!ELEMENT body (#PCDATA)>

]>

13

What is XML?

XSD

The XML Schema is the W3C replacement to DTDs

XSD supports data types an namespaces

XML Schemas are defined as XML

Allows you to define ordering/number of elements

Allows you to define mandatory elements

XML Schemas are extensible

14

XSD Example

<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">

<xsd:element name="product" type="ProductType"/>

<xsd:complexType name="ProductType">

<xsd:sequence>

<xsd:element name="number" type="xsd:integer"/>

<xsd:element name="size" type="SizeType"/>

</xsd:sequence>

<xsd:attribute name="effDate" type="xsd:date"/> </xsd:complexType>

<xsd:simpleType name="SizeType">

<xsd:restriction base="xsd:integer"> <xsd:minInclusive value="2"/>

<xsd:maxInclusive value="18"/> </xsd:restriction>

</xsd:simpleType>

</xsd:schema>

15

What is XML?

RELAX NG

XML and non-XML formats

Simpler than XSD

More like a speaking dialect than an XML dialect

Supports data types and namespaces

Not as robust as XSD (fewer data types, not as many rules

(defaults and such)‏

Not as widely utilized as XSD

16

RELAX NG (XML) Example

<element name="patron"

xmnln="http://relaxng.org/ns/structure/1.0">

<interleave>

<element name="name"><text/></element>

<element name="id-num"><text/></element>

<zeroOrMore>

<element name="book">

<choice>

<attribute name="isbn"/>

<attribute name="title"/>

</choice>

</element>

</zeroOrMore>

</interleave>

</element>

17

RELAX NG (Compact) Example

element patron {

element name { text } &

element id-num { text } &

element book {

(attribute isbn { text } |

attribute title { text } )

}*

}

18


Object Data Type

Clob based

Well formed check

Validating and Non-Validating

May contain XML fragments

19

XML Document

<onlyoneroot>

data goes here

</onlyoneroot>

XML Content (fragment)‏

<name>Lewis</name><sex>yes</sex>

20


Declare a column as XML

create table xml_tab (

id integer,

data XMLType );

Declare a variable as XML

DECLARE

v_xml XMLType;

BEGIN

……

21


What is SQL/XML?

SQL/

XML

22

What is SQL/XML?

SQL/XML (or SQL/X) is standards based

Combines XML and SQL

IBM, Oracle, Microsoft and Sybase all played a large

part in defining SQL/XML

Home on the web (but no longer maintained):

www.sqlx.org

23

What is SQL/XML?

SQL/XML defines a set of mappings and a set

of functions

Based on XQuery and XPath

Oracle implements the core functions of

SQL/XML

XQuery is also supported

24

What is SQL/XML?

SQL/X Functions

XMLParse

XMLSerialize

XMLSequence

XMLTable

XMLElement

XMLForest

XMLAgg

XML Comment

XMLConcat

More

25

What is SQL/XML?

Sample data

CREATE TABLE EMP

(

LAST_NAME VARCHAR2(50),

EMP_ID NUMBER NOT NULL,

FIRST_NAME VARCHAR2(50),

DEPT_ID NUMBER,

SALARY NUMBER,

CONSTRAINT EMP_pkey PRIMARY KEY (EMP_ID)‏

‏(

26

What is SQL/XML?

Sample sample data: INSERT INTO EMP(

LAST_NAME, EMP_ID, FIRST_NAME, DEPT_ID, SALARY)‏

VALUES

('Blow', 1, 'Joe', 1, 10000);

Also INSERT.....

('Head', 2, 'Helmut', 1, 12000),

('Jack', 3, 'Noe', 1, 12000),

('Hard', 4, 'Blow', 2, 20000),

('First', 5, 'Hugo', 2, 21000),

('Spaem',6, 'Kingoof', 2, 20000),

('Ventura', 7, 'Ace', 3, 35000),

('Nickleby', 8, 'Nick', 3, 400000),

('Budd', 9, 'Billy', 4, 99000),

('Cleaver', 10, 'Wally', 4, 100000) ;

27

What is SQL/XML? - XML Parse

The XMLType constructor, or the SQL/XML

function XMLParse, will convert text (or clobs)

into XML

vXMLVar XMLType;

vXMLVar := XMLType(‘<root>data</root>’);

vXMLVar := XMLParse(DOCUMENT

‘<root>data</root>’);

28

What is SQL/XML? -

XMLSerialize

XMLSerialize turns XML into text (you can also use

XMLType.toString)‏

vString := XMLSerialize(

DOCUMENT v_xml AS VARCHAR2);

vString := XMLSerialize(

CONTENT v_xml AS CLOB);

29

What is SQL/XML? -

XMLElement SELECT XMLElement(name main, last_name) from emp;

<main>Blow</main>

<main>Head</main>

<main>Jack</main>

<main>Hard</main>

<main>First</main>

30

What is SQL/XML? – XMLElement‏Cont’d

SELECT XMLElement(name main, last_name),

XMLElement(name main, first_name)‏

FROM emp;

<MAIN>Blow</MAIN> | <MAIN>Joe</MAIN>

<MAIN>Head</MAIN> | <MAIN>Helmut</MAIN>

<MAIN>Jack</MAIN> | <MAIN>Noe</MAIN>

<main>Hard</main> | <main>Blow</main>

31

What is SQL/XML? - XMLForest

SELECT XMLForest(last_name, first_name)‏

FROM emp;

<LAST_NAME>Blow</LAST_NAME><FIRST_NAME>Joe</F

IRST_NAME>

<LAST_NAME>Head</LAST_NAME><FIRST_NAME>Helmut

</FIRST_NAME>

32

What is SQL/XML? –

XMLForest‏Cont’d

SELECT XMLElement(name main,

XMLForest(last_name, first_name) )‏

FROM emp;

<MAIN>

<LAST_NAME>Blow</LAST_NAME>

<FIRST_NAME>Joe</FIRST_NAME>

</MAIN>

<MAIN>

<LAST_NAME>Head</LAST_NAME>

<FIRST_NAME>Helmut</FIRST_NAME>

</MAIN>

33

What is SQL/XML? – XMLAgg

SELECT XMLAgg(

XMLForest(last_name, first_name) )‏

FROM emp;





<LAST_NAME>Jack</LAST_NAME>

<FIRST_NAME>Noe</FIRST_NAME>…

34

What is SQL/XML? – XMLAgg

Cont'd SELECT XMLElement(name main,

XMLAgg(XMLForest(last_name, first_name) ))‏

FROM emp;

<MAIN>





<LAST_NAME>Jack</LAST_NAME>

<FIRST_NAME>Noe</FIRST_NAME>…

</MAIN>

35

What is SQL/XML? – Concatenating Columns


XMLForest(last_name || ',' || first_name

AS fullname, salary) ) FROM emp;

<MAIN>

<FULLNAME>Blow,Joe</FULLNAME>

<SALARY>10000</SALARY>

</MAIN>

<MAIN>

<FULLNAME>Head,Helmut</FULLNAME>


</MAIN>

36

What is SQL/XML? – Concat and Attributes


XMLElement(name fullname,

XMLAttributes(dept_id), last_name || ',' || first_name ),

XMLForest(salary) ) FROM emp;

<MAIN>

<FULLNAME

DEPT_ID="1">Blow,Joe</FULLNAME>


</MAIN>

37

What is SQL/XML? -

XMLComment


XMLComment('Comment goes here'),

XMLForest(last_name, first_name))‏

FROM emp;

<MAIN>





</MAIN>

38

What is SQL/XML? - XMLConcat

SELECT XMLElement(name lastname,

last_name),

XMLElement(name firstname, first_name)‏

FROM emp;

<LASTNAME>Blow</LASTNAME>

<FIRSTNAME>Joe</FIRSTNAME>

<LASTNAME>Head</LASTNAME>

<FIRSTNAME>Helmut</FIRSTNAME>

39


XMLConcat Cont'd SELECT XMLConcat(

XMLElement(name lastname, last_name),

XMLElement(name firstname, first_name) )‏

FROM emp;

<LASTNAME>Blow</LASTNAME><FIRSTNAME>Joe</FIRS

TNAME>

<LASTNAME>Head</LASTNAME><FIRSTNAME>Helmut</F

IRSTNAME>

40


XMLConcat Cont'd SELECT XMLElement(name main,

XMLConcat(

XMLElement(name lastname, last_name),

XMLElement(name firstname, first_name) ) )‏

FROM emp;

<MAIN><LASTNAME>Blow</LASTNAME><FIRSTNAM

E>Joe</FIRSTNAME></MAIN>

<MAIN><LASTNAME>Head</LASTNAME><FIRSTNAM

E>Helmut</FIRSTNAME></MAIN>

41

What should(n’t) I do with XML?

XML

42

What‏should(n’t)‏I‏do‏with‏XML?

Oracle is a RELATIONAL database

Store your data relationally, unless

Your XML is read only

Your XML is transient

Your XML is fairly static

Your XML is very small

You have a discrete key external to the XML

Preserved white space is critical

43

What should I do with XML?

Convert your XML to Relations by Shredding

Map your relational schema to the XML by its Schema or DTD

Use XPath to extract columnar data

Use SQL/XML to recreate the original XML document

44

What‏should(n’t)‏I‏do‏with‏

XML? Cont'd Relational data is much easier to

Index

Update

Manipulate

XML data is better for

Use by some programming languages

CMS systems

Very unstructured data

For reporting

Web 2.0 (AJAX, SOAP, Etc)‏

45

What‏should(n’t)‏I‏do‏with‏

XML? Cont'd XML is great for

Public stored procedure interfaces

Publish the XML spec

Include a version element or attribute

Change parameters and let users adapt over time

Web based processing

Many web apps support XML

XML + XSLT = Web Happiness

Data interfaces

Platform independent

Current parsers are fast

Validation and versioning built-in

Public Specifications

46

SQL/XML for Developers

Lewis Cunningham Data Architect, JP Morgan Chase http://it.toolbox.com/blogs/oracle-guide http://databasewisdom.com/

ODTUG Kaleidoscope 2009 06/21/2009

SQL/XML for Developers - Database Wisdomdatabasewisdom.com/pdf/sqlxml_for_developers_odtug_2009.pdf · SQL/XML for Developers Lewis Cunningham Data Architect, JP Morgan Chase ODTUG

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