Entities Entities

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Ü Ü bung 2 bung 2

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Ü Ü bung 2 bung 2

Fragen zur Vorlesung?Fragen zur Vorlesung?

In Depth: EntitiesIn Depth: Entities

MusterlMusterlöösung des Üsung des Übungblattes 1bungblattes 1

MusterlMusterlöösung des Üsung des Übungsblattes 2bungsblattes 2

Weitere Musterfragen Weitere Musterfragen

XML Tools: using Eclipse with DTDsXML Tools: using Eclipse with DTDs

XML Extra: other schema languagesXML Extra: other schema languages

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In Depth: Entities

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Entities Entities

Built

Built--in Entitiesin Entities

e.g. & or >

predefined

Character Entities Character Entities

e.g. ó or ó

predefined

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Entities Entities

General Entities General Entities

<!ENTITY empty-x-y "<x></x><y></y>">

Entity name is a valid XML name

Entity value can be anything as long as it is well formed

Entity values can contain other entities!

Entity reference in XML document: &empty-x-y;

Can be used in DTD where they will eventually be

included in the XML document, e.g. attribute default value

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External Parsed Entities

• Entity values can be external to the entity declaration

<!ENTITY footer SYSTEM „/mypages/footer.xml“>

• As element CDATA but not allowed in attributes

• Validating parsers must retrieve external entities

• The resulting document (after insertion of an external entity) must be well formed, the entity value itself must not be well formed

• There are also external unparsed entities, for non-XML

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Entities

Parameter Entities Parameter Entities

<!ENTITY % shared „childelement1 childelement2">

Element and attribute declarations may re-use structure

Parameter entities allow this shared structure to be placed in one location

Entity reference in DTD: %shared;

<!ELEMENT parentelement %shared;>

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Internal and External DTD Subset

• <!DOCTYPE BookStore SYSTEM „book.dtd“ [

<!ELEMENT BookStore (Book|BookStore)*>

]>

• Between […] is the internal DTD subset

• After the SYSTEM keyword is the external DTD subset

• DTD subsets can not override each others‘ element and attribute declarations

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Overriding Entities

• Parameter entities are more useful with external DTDs

• They can be redefined by the internal DTD subset

• If case of a conflict, the internal DTD subset has precedence

• External parameter entities are also useful to split large DTDs into smaller external subsets

• To include them at validation time, declare an external parameter entity and then use the entity reference

<!ENTITY % names SYSTEM „names.dtd“>

%names;

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Entities in DTDs and XML Schema

• Shocking but true: there is something in DTDs that can not be done in XML Schema…

declaring entities!

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Musterl

Musterl ö ö sung des sung des

Ü Ü bungsblattes 1 bungsblattes 1

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Wie kann Wohlgeformtheit bzgl. XML 1.0 und 1.1 erreicht Wie kann Wohlgeformtheit bzgl. XML 1.0 und 1.1 erreicht

werden?

streng genommen gar nicht!

Grund: XML-Deklaration

entweder nicht vorhanden Î nicht wohlgeformt bzgl.

XML 1.1

oder vorhanden, dann

- entweder version="1.0" Î nicht wohlgeformt bzgl.

XML 1.1

- oder version="1.1" Î nicht wohlgeformt bzgl. XML

Wohlgeformtheit bzgl. XML 1.0/1.1

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Was kann erreicht werden?

Sowohl XML

Sowohl XML--1.01.0--Parser als auch XMLParser als auch XML--1.11.1--Parser kParser köönnen nnen das Dokument verarbeiten.

das Dokument verarbeiten.

Und wie?

keine XML-Deklaration oder eine mit version="1.0"

XML-1.0-Parser ;

XML-1.1-Parser:

- XML 1.1 verlangt von Parsern, dass beide Versionen erkannt werden:

- wenn keine XML-Deklaration oder explizit Version 1.0: Wohlgeformtheit gemäß XML 1.0 ;

- in allen anderen Fällen: Wohlgeformtheit gemäß XML

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Musterlösung

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Musterlösung mit Standardnamensraum

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Musterlösung

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Musterlösung

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Musterlösung

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Musterlösung (Teil 2)

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Musterl

Musterl ö ö sung des sung des

Ü Ü bungsblattes 2 bungsblattes 2

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ipoDefaultNS.xml: purchaseOrder

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Deklaration von purchaseOrder Deklaration von purchaseOrder

<?xml version="1.0" encoding="UTF-8"?>

<!ELEMENT purchaseOrder (shipTo, billTo, Items)>

<!ATTLIST purchaseOrder

xmlns:xsi CDATA #FIXED "http://www.w3.org/2001/XMLSchema-instance"

xmlns CDATA #FIXED "http://www.altova.com/IPO"

xmlns:ipo CDATA #FIXED "http://www.altova.com/IPO"

orderDate CDATA #REQUIRED >

Probleme:

funktioniert nur mit Präfixen xsi und ipo

funktioniert nur mit Standard-Namensraum:

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ipoDefaultNS.xml: shipTo

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Deklaration von shipTo Deklaration von shipTo

<!ELEMENT shipTo (name, street, city, (postcode | (state, zip)))>

<!ATTLIST shipTo

export-code CDATA #IMPLIED

xsi:type (ipo:EU-Address | ipo:US-Address) #REQUIRED

>

Probleme:

kein Zusammenhang zwischen Struktur von shipTo und xsi:type

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ipoDefaultNS.xml: billTo

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Deklaration von billTo Deklaration von billTo

<!ELEMENT billTo (name, street, city, (postcode | (state, zip)))>

<!ATTLIST billTo

>

Problem:

kein Zusammenhang zwischen Struktur von billTo und xsi:type

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ipoDefaultNS.xml: Items und item

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Deklarationen von Items und item Deklarationen von Items und item

<!ELEMENT Items (item+)>

<!ELEMENT item (productName, quantity, price, comment?, shipDate)>

<!ATTLIST item partNum CDATA #REQUIRED>

<!ATTLIST item partNum IDID #REQUIRED>

oder besser

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Die restlichen Deklarationen Die restlichen Deklarationen

<!ELEMENT name (#PCDATA)>

<!ELEMENT street (#PCDATA)>

<!ELEMENT city (#PCDATA)>

<!ELEMENT postcode (#PCDATA)>

<!ELEMENT state (#PCDATA)>

<!ELEMENT zip (#PCDATA)>

<!ELEMENT productName (#PCDATA)>

<!ELEMENT quantity (#PCDATA)>

<!ELEMENT price (#PCDATA)>

<!ELEMENT comment (#PCDATA)>

<!ELEMENT shipDate (#PCDATA)>

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Deklaration von shipTo und billTo Deklaration von shipTo und billTo

<!ELEMENT shipTo (name, street, city, (postcode | (state, zip)))>(name, street, city, (postcode | (state, zip)))

<!ATTLIST shipTo

export-code CDATA #IMPLIED

>

<!ELEMENT billTo (name, street, city, (postcode | (state, zip)))>(name, street, city, (postcode | (state, zip)))

<!ATTLIST billTo

>

an zwei Stellen identische Strukturen

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Verbesserte Version Verbesserte Version

<!ENTITY % Address "(name, street, city,(postcode|(state, zip)))">

<!ELEMENT shipTo %Address;>

<!ELEMENT billTo %Address;>

Ö wird Parameter Entity genannt

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Musterfragen

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DTDs vs. XMLSchema DTDs vs. XMLSchema

To which of the following DTD declarations is the "self"

attribute above equivalent?

1. <!ATTLIST ethnos self (#PCDATA) #REQUIRED>

2. <!ATTLIST ethnos self PCDATA #REQUIRED>

3. <!ATTLIST ethnos self CDATA #FIXED>

4. <!ATTLIST ethnos self PCDATA #IMPLIED>

5. <!ATTLIST ethnos self CDATA #REQUIRED>

<xs:element name="ethnos">

<xs:complexType>

<xs:attribute name="self" type="xs:string" use="required"/>

</xs:complexType>

</xs:element>

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Was k

Was k ö ö nnte g nnte g ü ü ltig sein? ltig sein?

A. <?xml version="1.0"?>

<!DOCTYPE galaxy SYSTEM "cosmos.dtd">

B. <?xml version="1.0" encoding="UTF-8" ?>

<!DOCTYPE galaxy [ <!ELEMENT galaxy (#PCDATA)> ]>

C. <?xml version="1.0"?>

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

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Was k

Was k ö ö nnte g nnte g ü ü ltig sein? ltig sein?

D. <?xml version="1.0">

<!DOCTYPE galaxy SYSTEM

"http://www.example.com/cosmos.dtd">

E. <?xml version="1.0"?>

<!DOCTYPE PUBLIC "http://www.example.com/cosmos.dtd">

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Entity Declarations Entity Declarations

What value will the expression &species; yield in an instance document based on this DTD?

1. erectus 2. habilis 3. sapiens 4. (empty)

<!ENTITY species "erectus">

<!ENTITY species "habilis">

<!ENTITY species "sapiens">

<!ENTITY species "">

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Attribut

Attribut - - Deklarationen Deklarationen

According to this definition:

1. The name of the y element must match the name of an unparsed entity defined in the DTD.

2. The value of the y element must match the name of an unparsed entity defined in the DTD.

3. The name of the y attribute must match the name of an unparsed entity defined in the DTD.

4. The value of the y attribute must match the name of an unparsed entity defined in the DTD.

5. None of the above.

<!ATTLIST x y ENTITY #REQUIRED>

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Element

Element - - Deklarationen Deklarationen

Which XML would be successfully validated?

A. <train />

B. <train>

<engine> That Could </engine>

</train>

<!ELEMENT train (engine?, wagon*)>

<!ELEMENT engine (#PCDATA)>

<!ELEMENT wagon (#PCDATA)>

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Element

Element - - Deklarationen Deklarationen

C. <train>

<engine> That Could

<wagon> Caboose </wagon>

</engine>

</train>

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Element

Element - - Deklarationen Deklarationen

D. <train>

<wagon> Pullman </wagon>

<wagon> Diner </wagon>

</train>

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Element

Element - - Deklarationen Deklarationen

E. <train>

<wagon> Wagon-Lits </wagon>

</train>

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Was w

Was w ä ä re g re g ü ü ltig? ltig?

A. <audio_presentation modality="au|wav">&data;</audio_presentation>

B. <audio_presentation modality="wav">&data;</audio_presentation>

C. <audio_presentation>&data;</audio_presentation>

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE audio_presentation [

<!ENTITY data "c:.wav">

<!ELEMENT audio_presentation (#PCDATA)>

<!NOTATION au PUBLIC "au 1.0" "http:\\www.example.com.exe">

<!NOTATION wav PUBLIC "wav 1.0" "http:\\www.example.com.exe">

<!ATTLIST audio_presentation modality NOTATION (au|wav) #REQUIRED>

]>

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XML Tools

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XML Extra: other

schema languages

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What is Relax NG?

RELAX NG is a schema language for XML. The key features of RELAX NG are that it:

• is simple

• is easy to learn

• has both an XML syntax and a compact non-XML syntax

• does not change the information set of an XML document

• supports XML namespaces

• treats attributes uniformly with elements so far as possible

• has unrestricted support for unordered content

• has unrestricted support for mixed content

• has a solid theoretical basis

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Relax NG Relax NG

<text/>

</element>

<text/>

</element>

<text/>

</element>

</optional>

</element>

</zeroOrMore>

<!ELEMENT addressBook (card*)>

<!ELEMENT card (name, email, note?)>

<!ELEMENT name (#PCDATA)>

<!ELEMENT email (#PCDATA)>

<!ELEMENT note (#PCDATA)>

entspricht folg. DTD

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Relax NG Relax NG

kein W3C-, sondern OASIS-Standard

integriert Datentypen von XML-Schema:

<data type="integer"

datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes"/>

</element>

Konverter Relax NG Î XML-Schema:

http://thaiopensource.com/relaxng/trang.html

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