文件整合技術的新里程─ xml

葉慶隆大同大學資訊工程學系所

Email: [email protected]: http://www.cse.ttu.edu.tw/~chingyeh

文件整合技術的新里程─文件整合技術的新里程─ XMLXML

文件整合技術的新里程─ XML 2

內容內容

• XML 基本概念、背景說明、及應用• 用 DTD 定義 XML 文件的結構• XML Schema• 人與文件的關係• XML 相關標準： XSL 、 DOM 、 XML Query 、 XLink 、

SOAP• XML 在 EB 上的應用• UDDI: 網路服務的整合• 參考資料


文件的結構、內容、及格式• 文件的結構是指文件組成成分組合的方式

– 如一篇文章的章節段落– 請購單的欄位資料– 腳踏車組合手冊的簡介、組合程序、零件表、故障排除、索

引等• 文件的內容是指文件內實際的資料

– 如腳踏車組合手冊的文字、圖表等• 文件的格式是指將文件組成成分以一種視覺效果呈現

給讀者– 如黑體字、斜體字、內縮、段落加寬、表格等

• 文件結構和文件格式容易混淆


PRODUCT ADVISORYNumber: 146Type: PartsDate: 8/15/95

Subject: Revised Replacement Parts ...

Model 501 User Replaceable PartsThe parts list identified in the AnyCorp Model 501 ...New Parts List 1. 345-234 (Filter, cooling fan)2. 148-745 (Fuse, power: 1.5amp)3 ...

Product Advisory

Number: 146

Type: Parts

Date: 8/15/95

Revised:

Subject: Revised Replacement ...

Model 501 User-Replaceable Parts

The parts list identified in the ...

New Parts List

1. 345-234 (Filter, cooling fan)

2. 148-745 (Fuse, power: 1.5amp)

3. ...

文件的結構、內容、及格式


文件的結構、內容、及格式

• MS Word 著重文件格式之處理– 以格式功能將文件結構以視覺效果呈現給讀者– 人讀的懂，但電腦不易得知文件的內容

• HTML 文件係將格式以標記形式安插在文件中，加上 Internet 功能– 利用瀏覽器以視覺效果呈現給讀者，方便在網路上航行– 其呈現效果與 Word 文件類似

• XML 是一種標記語言。 XML 文件中的標記是用來表示文件中的結構資訊


HTML HTML 與與 XMLXML 的比較的比較

• HTML– SGML 在 Internet 上的應用– 一種資料呈現的技術– 不具擴充性的標記

• XML– SGML 的精簡版 +Internet 功能– 表現文件內容與結構– 可依所需自訂標記 (meta-language)


為什麼使用為什麼使用 XMLXML

• XML 可以表現文件內豐富的結構資訊，有利於網路上的應用

• HTML 受制於固定的標記，無法表達各式各樣的結構

• SGML 可以表達各式各樣的結構，但太複雜，製作成本高，不實用


XMLXML 小歷史小歷史

• 1996 年在西雅圖的集會中， SGML 專家探討如何結合 SGML 與 web

• Sun Microsystems 的 Jon Bosak 領導朝兩個方向討論1. 以 HTML 作為資訊格式的不足之處2. SGML 作為 web 應用標準的缺失

• “SGML on web” activity, 07/1996– 開始調適 SGML 成為合適於 web

• 10/02/1998 XML 1.0 誕生


XMLXML 的目標的目標

1. 便於在 Internet 上使用2. 支援各種應用3. 與 SGML 相容4. 易於寫程式處理 XML 文件5. 降低選擇性的特徵 (features)6. 人讀的懂7. XML 的設計要迅速8. XML 的設計要清楚和正規 (formal)9. XML 文件製作容易10.簡潔性並非重要考慮因素


XMLXML 應用應用

• Electronic commerce• Electronic data interchange (EDI)• Fine-grain content publishing• Internet search engines• Distributed application design• etc.


The XML CatalogThe XML Cataloghttp://www.xml.org/xmlorg_registry/index.shtmlhttp://www.xml.org/xmlorg_registry/index.shtml

• The XML Catalog lists organizations known to be producing industry-specificor cross-industry XML Specifications.

• Since XML activity is growing quickly, the list is likely to be incomplete. We would appreciate your sending us any updates or additions.


•Accounting•Advertising•Architecture and Construction•Architecture and Construction•Automotive•Aviation and Aerospace•Aviation and Aerospace•Bibliographies•Catalogs•Communication•Computer Graphics•Content Syndication•CRM - Customer Relationship Management•Data Mining•Defense Aerospace•Directory Services•Distributed Management•Economics•Education•Electronic Commerce•EDI - Electronic Data Interchange•Energy•Enterprise Information Portals•ERP - Enterprise Resource Planning•Financial and Capital Markets

•Food•Forms•Geography•Healthcare•Human Resources•Industrial Automation•Insurance•Legal•Middleware•Music•News•Publishing•Real Estate•Retail•Science•Software•SCM - Supply Chain Management•Translation and NLP•Travel•User Interface•Voice•Weather•Web Applications•Workflow

Complete list of the XML Catalog


定義定義 XMLXML 文件文件

• XML 文件的結構 ( 型態 ) 可以由「文件型態定義」 (document type definition, DTD) 、或是 Schema 來制定

• DTD 是透過元素 (element) 、屬性 (attribute) 、及實體 (entity) 等宣告，來制定文件結構的規則


定義定義 XMLXML 文件文件

<!DOCTYPE label[ <!ELEMENT label (name,street,city,state,country,code)> <!ELEMENT name (#PCDATA)> <!ELEMENT street (#PCDATA)> <!ELEMENT city (#PCDATA)> <!ELEMENT state (#PCDATA)> <!ELEMENT country (#PCDATA)> <!ELEMENT code (#PCDATA)> ]><label><name>Rock N. Robyn</name> <street>Jay Bird Street</street> <city>Baltimore</city> <State>MD</state> <country>USA</country> <code>43214</code></label>


Well-Formed and Valid DocumentsWell-Formed and Valid Documents

• XML has two different notions of “correct.”

• Valid documents– Declaring conformance to a DTD in a document type

declaration – “Using the right words in the right place”– Type-valid

• Well-formed documents– Markup is intelligible.– “Getting the pronunciation right”– Non-type-valid

DTD DTD 語法簡介語法簡介


DTDDTD 語法語法

• Seven major headings:– document type declarations– element types– attributes– entities– notations– conditional sections– processing instructions


文件類型宣告文件類型宣告Document Type DeclarationDocument Type Declaration

• 文件類型宣告定義了文件的邏輯結構規則、及一些相關的實體宣告 (entity)

• 規定文件的邏輯及實體結構• 規則可以含在文件類型宣告裡、存在外部檔案或二者



<?xml version “1.0”?><!DOCTYPE LABEL SYSTEM http://www.sgmlsource.com/dtds/label.dtd><LABEL>. . .</LABEL>

<!DOCTYPE label[ <!ELEMENT label (name,street,city,state,country,code)> <!ELEMENT name (#PCDATA)> <!ELEMENT street (#PCDATA)> <!ELEMENT city (#PCDATA)> <!ELEMENT state (#PCDATA)> <!ELEMENT country (#PCDATA)> <!ELEMENT code (#PCDATA)> ]><label><name>Rock N. Robyn</name> <street>Jay Bird Street</street> <city>Baltimore</city> <State>MD</state> <country>USA</country> <code>43214</code></label>



<?xml version “1.0”?><!DOCTYPE LABEL SYSTEM http://www.sgmlsource.com/dtds/label.dtd><LABEL>. . .</LABEL>

<!DOCTYPE GARAGESALE SYSTEM “garage.dtd”> <!ENTITY LOGO “logo.gif”>]><GARAGE>. . .</GARAGE>


元素類型宣告元素類型宣告Elements Type DeclarationElements Type Declaration

• 元素構成了 XML 文件的邏輯結構

Element Type Declaration[45] elementdecl ::= '<!ELEMENT' S Name S contentspec S? '>' [46] contentspec ::= 'EMPTY' | 'ANY' | Mixed | children

Element-content Models[47] children ::= (choice | seq) ('?' | '*' | '+')?[48] cp ::= (Name | choice | seq) ('?' | '*' | '+')?[49] choice ::= '(' S? cp ( S? '|' S? cp )* S? ')[50] seq ::= '(' S? cp ( S? ',' S? cp )* S? ')'


Elements Type DeclarationElements Type Declaration

<!ELEMENT spec (front, body, back?)><!ELEMENT div1 (head, (p | list | note)*, div2*)><!ELEMENT dictionary-body (%div.mix; | %dict.mix;)*><!ELEMENT p (#PCDATA|a|ul|b|i|em)*><!ELEMENT b (#PCDATA)>


屬性屬性AttributesAttributes

• 屬性賦予元素附加資訊 (meta-data) ，如安全等級、修改狀態、代號等

<!ATTLIST sample id ID #IMPLIED n CDATA #REQUIRED status (draft|final) “final”>

屬性名稱屬性值類型內定值


實體實體EntitiesEntities

• 有兩類實體– general entities: apply within the top-level and its attribut

e values.– parameter entities: apply within the internal and external

DTD subsets.


Entities: General EntitiesEntities: General Entities

<!ENTITY xml “Extensible Markup Language”>

<para>The &xml; is derived from ISO 8879, an International Standard<index label=&xml;> <para>

<para>The Extensible Markup Language is derived from ISO 8879, an International Standard<index label=“Extensible Markup Language”> <para>


Entities: Parameter EntityEntities: Parameter Entity

<!ENTITY %inline “#PCDATA|emphasis|link”>

<!ELEMENT para (%inline;)*>

<!ELEMENT para (#PCDATA|emphasis|link)*>


NotationsNotations

• Notations are used to include non-XML contents ─ like graphics, sounds, video , or source-code listing ─ in XML documents.

• While the XML parser knows nothing about the specific notations, it can pass them on to the processing software to let it know what kinds of data to handle.

<!NOTATION TeX PUBLIC “+//ISBN 0-201-13448-9::Knuth//NOTATION The TeXbook//EN”>


Conditional SectionsConditional Sections

• In the external DTD subsets and external parameter entities, XML allows conditional sections that the parser can include or ignore, depending on the value of the keywords at the start.

<![IGNORE [ <!ELEMENT para (#PCDATA)>]]>

<!ENTITY %include-para “IGNORE”><![%include-para;[ <!ELEMENT para (#PCDATA)>]]>

<!DOCTYPE book SYSTEM “book.dtd”[ <!ENTITY %include-para “INCLUDE”>]>

overriding a parameter entity


Processing InstructionsProcessing Instructions

• XML parser will pass PIs on to your application, but will be up to you to do something useful with them.

<?IS10744:arch name=“abc”>


Example: A DTD for B2B ECExample: A DTD for B2B EC

• RosettaNet PIP 3 A2 Price And Availability Query Version 1.2 Available at http://www.rosettanet.org


XML SchemaXML Schema

• The new XML Schema system aims at providing a rich grammatical structure for XML documents that overcomes the limitations of the DTD.


Limitations of DTDLimitations of DTD

• XML inherited DTDs from SGML. • DTDs can be used to define content models and, to

a limited extent, the datatypes of attributes, but they have a number of obvious limitations:– different (non-XML) syntax– no support for namespaces– extremely limited datatyping– a complex and fragile extension mechanism based on littl

e more than string substitution (no explicit relationship)


What is a Schema?What is a Schema?

• A schema is a model for describing the structure of information.

• In the context of XML, a schema describes a model for a whole class of documents.

• A schema might also be viewed as an agreement on a common vocabulary for a particular application that involves exchanging documents.



• In schemas, models are described in terms of constraints. • Two kinds of constraints that you can give:

– content model constraints describe the order and sequence of elements and

– datatype constraints describe valid units of data.



• For example, a schema might describe a valid <address> with the content model constraint that – it consists of a <name> element, followed by – one or more <street> elements, followed by – exactly one <city>, <state>, and <zip> element.– The content of a <zip> might have a further datatype cons

traint that it consist of either a sequence of exactly five digits or a sequence of five digits, followed by a hyphen, followed by a sequence of exactly four digits. No other text is a valid ZIP code.

<address> <name>Namron H. Slaw</name> <street>256 Eight Bit Lane</street> <city>East Yahoo</city> <state>MA</state> <state>CT</state> <zip>blue</zip></address>

invalid


Features of SchemaFeatures of Schema

• Richer datatypes – booleans, numbers, dates and times, URIs, integers, decimal nu

mbers, real numbers, intervals of time, etc.• User defined types• Attribute grouping• Refinable archetypes• Namespace support


ValidityValidity

• Reasons why need to validate documents: – EC: received is exactly what you expect.– B2B: validating before inserting into your database. – XML document for control purpose

• Content model validity tests whether the order and nesting of tags is correct.

• Datatype validity is the ability to test whether specific units of information are of the correct type and fall within the specified legal values.


Illustrations of XML SchemaIllustrations of XML Schema

An XML document fragment<InvoiceNo>123456789</InvoiceNo><ProductID>J123456</ProductID>

DTD fragment describing the above elements <!ELEMENT InvoiceNo (#PCDATA)><!ELEMENT ProductID (#PCDATA)>

XML Schema fragment describing the above elements<element name='InvoiceNo' type='positive-integer'/><element name='ProductID' type='ProductCode'/><simpleType name='ProductCode' base='string'> <pattern value='[A-Z]{1}d{6}'/></simpleType>


In BriefIn Brief

• Schemas greatly improves over DTDs. • Certain kinds of applications can be made

more interoperable by XML Schema. • DTDs are well understood and they do offer a

good way to describe the structure of an document for interchange.

• It will take some time before XML Schema are as well understood.


Types of Interaction with DocumentsTypes of Interaction with Documents

• Most documents stored in XML forms are created for the purpose of conveying information or keeping track of information.

• Types of interactions people have with documents:– creation and modification– management, storage, and archiving– utilization.


Printing

Import

Exchange

Searching andviewing

Creation

Types of Interaction with DocumentTypes of Interaction with Document

Workstation

UpdateWorkstation

Review/validation

Workstation

Conversion/transformation

Workstation

Document classificationDocument assemblyDocument archivalDocument storage

Useful databaseinformation

Document creationand modification

Document managementand storage

Document utilization

Workstation

Laser printer

Building alternatedocuments

Online searchingviewing,

exchange, export

Extraction,analysis


XSL: Transformation and StylingXSL: Transformation and Styling

• XSL is a language for expressing stylesheets. (www.w3.org)

• It consists of two parts:– XSL Transformations (XSLT): a language for transforming X

ML documents – An XML vocabulary for specifying formatting semantics (XS

L Formatting Objects)

XSL processor

XSL document(template rules)

XML document Output


DOM: Document Object ModelDOM: Document Object Model

• DOM is an API for HTML and XML– It defines the logical structure of documents and

the way a document is accessed and manipulated. – With the DOM, programmers can build

documents, navigate their structure, and add, modify, or delete elements and content.

• Language-independent



• DOM parsers– Xerces: xml.apache.org

• C++, Java, Perl

– IBM: www.alphaworks.ibm.com• Java, C++

– SUN: java.sun.com• Java

– MS: msdn.microsoft.com• IE, Data Channel XML Parser


DOM: Document DOM: Document Object ModelObject Model

• Abstract Tree Produced by XML Parser



• DOM operations:

getDocType

getName

getElementsByTagName

item

getFirstChild

getNodeValue

getAttribute

getChildNodes

getLength

getTagName


XML QueryXML Query

• Provide flexible query facilities to extract data from real and virtual documents on the Web, therefore finally providing the needed interaction between the web world and the database world.

• Ultimately, collections of XML files will be accessed like databases. (www.w3.org)


XLinkXLink

• XML Linking Language (XLink) allows elements to be inserted into XML documents in order to create and describe links between resources.

• It uses XML syntax to create structures that can describe the simple unidirectional hyperlinks of today's HTML, as well as more sophisticated links. (www.w3.org)


Simple Object Access Protocol: SOAPSimple Object Access Protocol: SOAP

• SOAP is a lightweight protocol for exchange of information in a decentralized, distributed environment.

• It is an XML based protocol that consists of three parts: 1. an envelope that defines a framework for describing what is in

a message and how to process it, 2. a set of encoding rules for expressing instances of application-d

efined datatypes, and 3. a convention for representing remote procedure calls and resp

onses. • SOAP can potentially be used in combination with a variety o

f other protocols; however, the only bindings defined in this document describe how to use SOAP in combination with HTTP and HTTP Extension Framework. (www.w3.org)


RosettaNetRosettaNet: : EB Supply Chain ManagementEB Supply Chain Management

• Independent, self-funded, nonprofit consortium

• Dedicated to the deployment of standard electronic business interfaces to align the processes between supply chain (www.rosettanet.org)


ebXMLebXMLwww.ebXML.orgwww.ebXML.org

• Electronic Business Extensible Markup Language (ebXML) is an international initiative established by the United Nations Centre for Trade Facilitation and Electronic Business (UN/CEFACT) and the Organization for the Advancement of Structured Information Standards (OASIS) with a mandate to undertake a 15-18 month program of work.

• The purpose of the ebXML initiative is to research and identify the technical basis upon which the global implementation of XML can be standardized.

• The goal is to provide an XML-based open technical framework to enable XML to be utilized in a consistent and uniform manner for the exchange of Electronic Business (EB) data in application to application, application to human, and human to application environments—thus creating a single global market. (ebXML.org)


UDDIUDDIUniversal Descriptions, Discovery and IntegrationUniversal Descriptions, Discovery and Integration

• Universal Description, Discovery and Integration (UDDI) is a specification for distributed Web-based information registries of Web services.

• UDDI is also a publicly accessible set of implementations of the specification that allow businesses to register information about the Web services they offer so that other businesses can find them. (www.uddi.org)



• Web services are the next step in the evolution of the World Wide Web (WWW) and allow programmable elements to be placed on Web sites where other can access distributed behaviors.

• UDDI registries are used to promote and discover these distributed Web services. (www.uddi.org)



• The programmatic interface provided for interacting with systems that follow the UUDI specifications make use of XML and a related technology, SOAP which is a specification for using XML in simple message based exchanges.

• The UDDI Programmers API Specification defines approximately 30 SOAP messages that are used to perform inquiry and publishing functions against any UDDI compliant service registry. (www.uddi.org)


參考資料參考資料• Todd Freter, “XML: Mastering Information on the Web,” htt

p://www.sun.com/980310/xml/;$sessionid$UCZMTEQAACPBDAMTA1FU45Q.

• Norman Walsh, “What is XML?” http://www.xml.com/pub/98/10/guide1.html.

• Norman Walsh, “A Technical Introduction to XML,” http://nwalsh.com/docs/articles/xml/.

• Eve Maler and Jeanne El Andaloussi, Developing SGML, DTDs: From Text to Model to Markup, Prentice Hall, 1996.

• Adam Bosworth, “Microsoft's Vision for XML,” SGML/XML '98, Paris

• Robin Cover, Introducing the Extensible Markup Language (XML), http://www.oasis-open.org/cover/xmlIntro.html