2 dtd - validating xml documents

DTD – Validating XML Documents

Atul Kahate

[email protected]

XML – A Quick Refresher

DTD | Atul Kahate 3

Exercise Create an XML document to store

student information in the following format: Roll Number Name Marks

Web Technologies XML J2EE Network Programming

Rank

DTD | Atul Kahate 4

Exercise We have a book titled Web

Technologies. Create an XML document that stores information about this book in the following format: Name: Web Technologies Part (1-3)

Chapters (Chapter 1-6) Sections (Section 1-3) Summary

DTD | Atul Kahate 5

Exercise Create an XML document to store

employee information in the following format: Employee Number Name Department Manager Name Projects assigned

Project 1 Project 2 Project 3

Designation

DTD | Atul Kahate 6

XML Naming rules Should contain at least one letter: a-z or

A-Z. Can start with an alphabet or

underscore. Can contain letters, digits, hyphens,

underscores, full stops.

Comments: Enclose in  tags. e.g. <!– This is a comment -->

DTD | Atul Kahate 7

Exercise Identify valid and

invalid element names from the list below <Project05> <PROJECT05> <Project.05> <_05Project> <project05> <project_05>

Identify valid and invalid element names from the list below <Project=05> <PROJECT:05> <Project 5> <Project%05> <05project> <.project.05>

DTD | Atul Kahate 8

Some XML Terminology DTD

Elements

Attributes

Entities

Markup

DTD | Atul Kahate 9

Terminology Snapshot<?xml version="1.0"?><?xml-stylesheet type="text/xsl" href="books_list.xsl"?>

<BOOKS><BOOK pubyear="1929">

<BOOK_TITLE>Look Homeward, Angel</BOOK_TITLE><AUTHOR>Wolfe, Thomas</AUTHOR>

</BOOK><BOOK pubyear="1973">

<BOOK_TITLE>Gravity's Rainbow</BOOK_TITLE><AUTHOR>Pynchon, Thomas</AUTHOR>


<BOOK_TITLE>Cards as Weapons</BOOK_TITLE><AUTHOR>Jay, Ricky</AUTHOR>


<BOOK_TITLE>Computer Networks</BOOK_TITLE><AUTHOR>Tanenbaum, Andrew</AUTHOR>

</BOOK></BOOKS>

XML tag

Root element

Element name

Element value

End element indicator

Start element indicator

Attribute name

Attribute Value

Document Type Definition (DTD)

DTD | Atul Kahate 11

Document Type Definition (DTD) Describes the components and

guidelines in an XML document Lists

Elements Attributes and their possible values Entities Interaction of all of the above

“Rule book” for an XML document


DTD Example<?xml version=“1.0” standalone=“yes”?><!DOCTYPE EMPLOYEE [

<!ELEMENT EMPLOYEE (ORG, NAME, DEPT, SALARY)><!ELEMENT ORG (#PCDATA)> <!ELEMENT NAME (#PCDATA)><!ELEMENT DEPT (#PCDATA)><!ELEMENT SALARY (#PCDATA)>

]><EMPLOYEE>

<ORG>test </ORG><NAME>Parag</NAME><DEPT>J2EE</DEPT><SALARY>10000</SALARY>

</EMPLOYEE>


Simple XML Example<?xml version=“1.0”?><message>

<header><date> 25 September 2004 </date><from> Me </from><to> You </to><subject> Test message </subject>

</header><body> Hello World</body><signature> XYZ company </signature>

</message>


DTD for this XML Example

<!ELEMENT message (header, body, signature)>

<!ELEMENT header (date, from, to, subject) >


Elements Used to organize information in an XML

document

Similar to HTML elements (e.g. <P> <P>)

Every XML document must have exactly one root element

Empty elements are shown by using <empty_element/>


Attributes Part of the element tag

Provide additional information about elements

Optional

Can be specified only in the element start tag

DTD Types


Types of DTD External

DTD and XML document are physically different documents

More common for professional documents

Internal DTD is declared inside the XML document Useful for simple documents


External DTD Declaration inside an XML document

<!DOCTYPE book SYSTEM http://www.example.com/dtd/book.dtd>

DTD declaration types SYSTEM – Specifies the URL from where the

parser can obtain the actual DTD PUBLIC – Does not specify a particular

location for the DTD


Example of External DTD Addressbook.xml<?xml version="1.0"?><!DOCTYPE DOCUMENT SYSTEM "addressbook.dtd"><ADDRESSBOOK>

<CONTACT><NAME> Name 1 </NAME><ADDRESS> Address 1 </ADDRESS><CITY> City 1 </CITY><PIN> Pin 1 </PIN><PHONE> Phone 1 </PHONE>

</CONTACT></ADDRESSBOOK>

Addressbook.dtd<!ELEMENT ADDRESSBOOK (CONTACT)><!ELEMENT CONTACT (NAME, ADDRESS, CITY, PIN, PHONE)><!ELEMENT NAME (#PCDATA)><!ELEMENT ADDRESS (#PCDATA)><!ELEMENT CITY (#PCDATA)><!ELEMENT PIN (#PCDATA)><!ELEMENT PHONE (#PCDATA)>


Internal DTD Example

<?xml version="1.0"?><!DOCTYPE EXAMPLE[

<!ELEMENT EXAMPLE (#PCDATA)>><EXAMPLE> Insert the comment:

</EXAMPLE>


Which DTD Type to Use? External DTDs

Allow sharing of one DTD among many XML documents

Allow keeping the structure (DTD) and data (XML) separate

Updates can be centralized Unnecessary duplications can be avoided

Internal DTDs Simpler to try out and test at first


Standalone XML Documents Do not have any external DTD May have an internal DTD Use of standalone keyword

<?XML version=“1.0” standalone=“yes”?>

… Use of the standalone keyword is

optional


Main Keywords used in DTD ELEMENT

Describes XML element type name and its permissible child elements

ATTLIST Declares XML element attribute names, plus

permissible/default values ENTITY

Declares special character references, text macros, or repetitive content

Declaring Elements in a DTD


Element markup

Symbol Name Description

<email>

Start tag

At the start of an element, the opening tag

Meeting Content In the middle of an element, its content

</email>

End tag At the end of an element, the closing tag


Element Markup – Note The element name in the start tag

and the end tag must match

e.g. the following is wrong<simple.text> This is wrong!

</simple.Text>


ELEMENT Declarations in a DTD – 1 ELEMENT tags are used to describe XML

elements in a DTD document The ELEMENT declaration can have one

of the following two forms<!ELEMENT name content_category><!ELEMENT name (content_model)> content_category and content_model

specify what kind of content can appear inside a given XML element


ELEMENT Declarations in a DTD – 2 content_category

Five types Any – Any well-formed XML data None (or Empty) – Cannot contain text or child

elements, but can contain attributes Text only – Can contain text, but no child elements Element only - Can contain child elements, but no text Mixed – Can contain a mixture of child elements and

text All these categories allow declarations of

attributes by using the ATTLIST tag


ELEMENT Declarations in a DTD – 3 ANY and EMPTY elements

Follow the first form of declaration, i.e. <!ELEMENT name content_cateogry>

ANY – Allows anything well-formed Example DTD declaration

<!ELEMENT AnythingAllowed ANY > Corresponding XML

<?xml version="1.0" encoding="utf-8" ?> <AnythingAllowed> <AChildElement>Hello</AChildElement> <AnotherChild> <ChildWithinChild>test</ChildWithinChild> </AnotherChild> </AnythingAllowed>

Or this <?xml version="1.0" encoding="utf-8" ?> <AnythingAllowed/>


ELEMENT Declarations in a DTD – 4 ANY and EMPTY elements … contd …

EMPTY – Cannot have text or sub-elements, but can contain attributes

Example DTD declarations <!ELEMENT employee EMPTY> <!ELEMENT building EMPTY>

Corresponding XML elements <employee></employee> <employee stillinservice = “true”/> <building name = “Main center”></building>


ELEMENT Declarations in a DTD – 5 Other categories

Element, Mixed, or PCDATA are used Syntax:

<!ELEMENT name (content_model) cardinality> Content models

Text only, Element only, or mixed Examples of each type follow

No content model is needed for ANY or EMPTY categories


ELEMENT Declarations in a DTD – 6 Content models

Text only <!ELEMENT name (#PCDATA) >

Element only <!ELEMENT name ((child1, child2) | (child3, child4)) >

Mixed <!ELEMENT name (#PCDATA | child1 | child2)* >

Two kinds of lists can appear within content models Sequence lists: Child elements must appear in the specified

order, using a comma to separate the element names as shown above

Choice lists: List of mutually exclusive child elements, separated by the pipe symbol as shown above


Sequence and Choice Lists – Another Example Choice Example

<!ELEMENT color (red | yellow | green)> Specifies that:

The color element must contain a red element, a yellow element, or a green element

Only one of these options can be chosen e.g. My favorite color is <color> <red> </red> </color> and

not so favorite color is <color> <yellow> </yellow> </color>.

Sequence and choice example:<! ELEMENT PersonName

((Mr | Ms | Dr), FirstName, MiddleName,

LastName))

>


ELEMENT Declarations in a DTD – 7 Text only (PCDATA) content

Only text data is allowed in the XML content DTD specifies this with the #PCDATA

keyword Example

DTD <!ELEMENT name (#PCDATA) >

XML <name>Atul Kahate</name>


ELEMENT Declarations in a DTD – 8 Element only content

Can contain child elements, but no text Example

DTD <!ELEMENT name (first, last) >

XML <name>

<first>Atul</first> </last>Kahate</last>

</name> The element name must contain exactly two child

elements first and last, and they must appear exactly once, in the specified sequence


ELEMENT Declarations in a DTD – 9 Mixed content

Allows child elements or text Example

DTD <!ELEMENT name (#PCDATA | (first, last) >

Allowed XMLs <name>Atul Kahate</name> OR <name>

<first>Atul</first> <last>Kahate</last>

</name>


Specifying Cardinality Used to specify how often an element or an element

group can repeat or be omitted ? specifies a zero or one occurrence

e.g. <!ELEMENT testing (one, two?, three)> Means that two can occur only once or not at all inside the

testing element * specifies zero or more times occurrence

e.g. <!ELEMENT match (result, round*)> Means that round can occur any number of times or not at

all inside the match element + specifies at least one or more occurrence

e.g. <!ELEMENT match (result, round+)> Means that round can occur at least once or more inside

the match element


Examples<!ELEMENT PersonName(

(Mr | Ms | Dr)?, FirstName, MiddleName*, LastName))>

<!ELEMENT PersonName(

SingleName |((Mr | Ms | Dr)?, FirstName, MiddleName*, LastName))

)>


Corresponding XML data <PersonName>

<Mr /><FirstName>Sachin</FirstName><LastName>Tendulkar</LastName>

</PersonName>

<PersonName><FirstName>Sachin</FirstName><LastName>Tendulkar</LastName>

</PersonName>

<PersonName><SingleName>Tendulkar</SingleName>

</PersonName>


Exercise For the following XML document, create

a DTD

<?xml version="1.0"?><ADDRESSBOOK>

<CONTACT><NAME> Name 1 </NAME><ADDRESS> Address 1 </ADDRESS><CITY> City 1 </CITY><PIN> Pin 1 </PIN><PHONE> Phone 1 </PHONE>

</CONTACT></ADDRESSBOOK>


Exercise Solution: DTD

<!ELEMENT ADDRESSBOOK (CONTACT)><!ELEMENT CONTACT (NAME, ADDRESS,

CITY, PIN, PHONE)><!ELEMENT NAME (#PCDATA)><!ELEMENT ADDRESS (#PCDATA)><!ELEMENT CITY (#PCDATA)><!ELEMENT PIN (#PCDATA)><!ELEMENT PHONE (#PCDATA)>


Exercises – 1 We want to keep the following

information regarding cricket scores. Suggest a DTD structure.

Batting Team Opposition Team Innings (1 or 2) Batting position (1 to 11) Batsman Name How Out? (e.g. caught Hayden, or not out) Bowler (e.g. McGrath, or not applicable) Runs scored


Exercises – 2 A college wants to maintain the following

information about its students. Design a DTD. Roll number of student Student name (Composed of first, middle, and last names; or as a

single name without any split) Trimester Number Subject Type (Compulsory or Elective) Maximum Marks Marks Obtained Total Maximum Marks Total Marks Obtained Percentage Result Rank


Exercises – 3 Create a DTD for this XML:<?xml version="1.0"?><order>

<items><item>

<item_code>A001</item_code><item_name>Book</item_name><item_quantity>2</item_quantity><item_rate>100</item_rate>

</item><item>

<item_code>B001</item_code><item_name>Watch</item_name><item_quantity>3</item_quantity><item_rate>75</item_rate>

</item></items><contact>

<customer_code>G6171612</customer_code><customer_name> test test</customer_name><customer_address>

<address_1>43 Navi Peth</address_1><address_2>Main building</address_2><city>Pune</city><state/><country>India</country><pin>411001</pin><phone_details>

<home_landline>25530833</home_landline><work>22981011</work><mobile>98111-32111</mobile>

</phone_details></customer_address>

</contact><payment_details>

<payment_method>credit card</payment_method><card_number>191921000102101188</card_number><brand>visa</brand><expiry_date>02-11</expiry_date><cheque_number/><cheque_issuing_bank/><amount>500</amount>

</payment_details></order>

Entities


Entities Unit of data Can contain binary data, images,

textual information, etc Included inside an XML document with

the & symbol Generally contain

Frequently used phrases Text strings Chunks of text


Entity Example DTD<!ELEMENT list (name*)><!ELEMENT name (#PCDATA)><!ENTITY prof "Professor">

XML<?xml version="1.0"?>

<!DOCTYPE list SYSTEM "professor.dtd">

<list><name>&prof; Douglas Comer</name><name>&prof; Andrew Tanenbaum</name>

</list>


Pre-defined Entities Available as a default

amp: ampersand (&) apos: apostrophe (‘) gt: greater than (>) lt: less than (<) quot: quotation mark (“)

Using the default entitiesPlease make sure that your offer is > $500Please make sure that your offer is > $500

Attributes


Usage of Attributes Example without attributes

<Person> <FirstName>Maithili</FirstName> <LastName>Shetty</LastName> <Department>Software</Department>

</Person> Same example, with all child elements

changed to attributes <Person FirstName=“Maithili”

LastName=“Shetty” Department=“Software” />


Specifying an Attribute

Symbol Description

< Start tag open delimiter

element.name Element name

attribute.name Attribute name

= Value indicator

‘ Attribute value start

Value Value of the attribute

‘ Attribute value end

> Start tag close delimiter


Attribute Declarations Used to describe the attributes inside an

element Syntax: <!ATTLIST element.name

attribute.definitions> Significance

Declares the names of the allowed attributes States the type of each attribute Makes it possible to specify a default value for each

attribute Each attribute declaration is as follows:

attribute.name attribute.type


Example Containing Entities and an Attribute<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE Invoice [

<!ENTITY copy "©"><!ENTITY Vendor "i-flex solutions limited"><!ENTITY Disclaimer "No warranty! © 2007 &Vendor;"><!ENTITY char_A "A"><!ELEMENT Invoice (Notice*)><!ATTLIST Invoicename CDATA #REQUIRED

><!ELEMENT Notice (#PCDATA)>

]><Invoice name="&Vendor;">

<Notice>&Disclaimer;</Notice><Notice>And here is &char_A;</Notice>

</Invoice>


Declaring Multiple Attributes<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE PersonName [

<!ELEMENT PersonName EMPTY><!ATTLIST PersonNametitle CDATA #REQUIRED

first CDATA #REQUIREDmiddle CDATA #REQUIREDlast CDATA #REQUIRED

>]><PersonName title="Mr" first="test" middle="test"

last="test"/>


Attribute Defaults We can specify if an attribute is

mandatoryAttribute Default Description

#REQUIRED Must appear

#IMPLIED Optional

#FIXED Optional, but if appears, must have the default value

Default value without any keyword

Optional, but if appears, can have any value conforming to its data type


Attributes - #REQUIRED DTD

<!ATTLIST Employee Height CDATA #REQUIRED>

Invalid XML <Employee>Hiten</Employee>

Valid XML <Employee

Height=“165”>Hiten</Employee>


Attributes - #IMPLIED DTD

<!ATTLIST Employee Height CDATA #IMPLIED>

Valid XML <Employee>Hiten</Employee>

Valid XML <Employee

Height=“165”>Hiten</Employee>


Attributes - #FIXED DTD

<!ELEMENT Employee (#PCDATA)> <!ATTLIST Employee Height CDATA #FIXED

“160”> Invalid XML

<Employee Height=“165”>Hiten</Employee> Valid XML

<Employee Height=“160”>Hiten</Employee> Valid XML

<Employee>Hiten</Employee>


Attributes – Default Values DTD

<!ELEMENT Employee (#PCDATA)> <!ATTLIST Employee Height CDATA “160”>

Valid XML <Employee Height=“165”>Hiten</Employee>

Valid XML <Employee Height=“160”>Hiten</Employee>

Valid XML <Employee>Hiten</Employee>


Important Attribute Types CDATA – Character data (Simple text

string) Enumerated values – One from a list of

values


CDATA Attribute Type Strings of characters

Any attribute that does not have anything specified is defaulted to string

Example <!ATTLIST book owner CDATA> DTD <book owner=“British library”> XML


Enumerated Attribute Type Lists of possible vales Example

<!ELEMENT fruit> <!ATTLIST fruit COLOR (RED | GREEN | PINK)

“RED”> RED is the default value


Exercise Create a DTD for the following XML example: <?xml version = "1.0"?>

<!DOCTYPE letter SYSTEM "letter.dtd">

<letter> <contact type = "sender"> <name>Nitin Pathak</name> <address>PO Box 1230</address> <address>Nigdi Post Office</address> <city>Pune</city> <pin>411001</pin> <state>Maharashtra</state> <flag gender = "M" /> </contact>

<contact type = "receiver"> <name>Leena Mohan</name> <address>PO Box 6171</address> <address>Thane Post Office</address> <city>Thane</city> <pin>400602</pin> <state>Maharashtra</state> <flag gender = "F" /> </contact>

<salutation>Dear madam:</salutation>

<paragraph>We are pleased to inform you that you have been selected for the position of assistant programmer</paragraph>

<paragraph>Please confirm your acceptance via a return letter</paragraph>

<closing>Sincerely,</closing>

<signature>Nitin Pathak - General Manager</signature> </letter>


Solution <!ELEMENT letter (contact+, salutation, paragraph+, closing,

signature)> <!ELEMENT contact (name, address+, city, pin, state, flag)> <!ELEMENT salutation (#PCDATA)> <!ELEMENT paragraph (#PCDATA)> <!ELEMENT closing (#PCDATA)> <!ELEMENT signature (#PCDATA)> <!ELEMENT name (#PCDATA)> <!ELEMENT address (#PCDATA)> <!ELEMENT city (#PCDATA)> <!ELEMENT pin (#PCDATA)> <!ELEMENT state (#PCDATA)> <!ELEMENT flag EMPTY> <!ATTLIST contact type CDATA #IMPLIED> <!ATTLIST flag gender (M | F) "M">


Case Study – Book information LIBRARY.DTD file describes the

documentElement DescriptionBOOK Identifies a book record

TITLE Describes a book’s title

AUTHOR Author of the book

PUBLISHER

Publisher of the book

COVER Hardback or paperback

CATEGORY Fiction, Fantasy, Sci-fi, etc

ISBN ISBN number

RATING Scale of 1-5

COMMENTS

Comments


Case Study – Elements<!ELEMENT book><!ELEMENT title><!ELEMENT author><!ELEMENT publisher><!ELEMENT cover EMPTY><!ELEMENT category EMPTY><!ELEMENT isbn><!ELEMENT rating EMPTY><!ELEMENT comments>


Case Study – Modified Elements Declaration (Nesting)<!ELEMENT book (title, author, publisher, cover,

category, isbn, rating, comments?)><!ELEMENT title (#PCDATA)><!ELEMENT author (#PCDATA)><!ELEMENT publisher (#PCDATA)><!ELEMENT cover EMPTY><!ELEMENT category EMPTY><!ELEMENT isbn (#PCDATA)><!ELEMENT rating EMPTY><!ELEMENT comments (#PCDATA)>


Case Study – Let us put it all together<?xml version="1.0" standalone="yes"?>

<!DOCTYPE BOOK[

<!ELEMENT book (title, author, publisher, cover, category, isbn, rating, comments?)>

<!ELEMENT title (#PCDATA)>

<!ELEMENT author (#PCDATA)>

<!ELEMENT publisher (#PCDATA)>

<!ELEMENT cover EMPTY>

<!ATTLIST cover type (HARDBACK | PAPERBACK) "PAPERBACK">

<!ELEMENT category EMPTY>

<!ATTLIST category type (FICTION | FANTASY | SCIFI | MYSTERY | HORROR | NONFICTION |

HISTORICAL | BIOGRAPHY) "FICTION">

<!ELEMENT isbn (#PCDATA)>

<!ELEMENT rating EMPTY>

<!ATTLIST rating type (1 | 2 | 3 | 4 | 5) "3">

<!ELEMENT comments (#PCDATA)>

]>

<book>

<title>Computer Networks</title>

<author>Andrew Tanenbaum</author>

<publisher>Pearson Edcation</publisher>

<cover type="PAPERBACK"></cover>

<category></category>

<isbn>0-07-066789-X</isbn>

<rating type="5"></rating>

<comments> Easily the best of the best!</comments>

</book>

Thank you!

Any Questions?

2 dtd - validating xml documents

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