(1) What are the primary differences between XML and HTML

(1) What are the primary differences between XML and HTML?

The differences between HTML and XML could be defined in broad strokes such as the following:

“HTML is a DTD for SGML and XML is a subset of SGML”

http://matwww.ee.tut.fi/hmopetus/prj/xmlsem2000/ht/leppanen.htm

Accessed 07/26/2003

-Or you could attempt to define the more specific differences-

“…End tags are required (XML).

(Not always so HTML-FSH)

All attributes have to be fully quoted with either single or double quotes (XML).

(Not always so HTML-FSH)

Tags have to be properly nested (XML).

(Usually in HTML-FSH)

Tag names have to be in lower-case (XHTML only).

(Not so HTML-FSH)

XML documents have to be well-formed (XML).

(Not always so HTML-FSH)

Duplicate attributes are not allowed (XML).

Attribute values must be properly escaped (XML)…etc.”

http://www.html2xml.com/Html2XmlDifferences.asp

Accessed 07/26/2003

-Or-

In XML one and only root element

XML tags have a distinct start and end components.

All XML tags are nested correctly.

All XML attribute values are quoted.

Empty XML elements are formatted correctly.

-While this is not (strictly speaking) the case with HTML

But the primary differences could most accurately be stated as:

XML tags are about preserving and defining the information contained within them (i.e. content: essentially giving one the ability to define a new, distinct mark-up language.)

HTML is more concerned with presentation of information within a browser.

HTML in a browser window is much more “forgiving” with regard to syntax than XML, and will generally display as intended even with “errors”.

XML must maintain a very specific and accurate structure in order for the document information to be reused. (FSH 07/26/2003)

“HTML is a language used for data presentation and formatting, XML’s

emphasis is on data content.”

XML New Perspectives, Patrick Carey, Course technology 2002 p 1.07

(2) Why was XML created?

XML can be used in a wide variety of applications, but the bottom line is this: It's a way to represent data. In some cases, that data is intended for a database; in others, it's meant to be read by a person.

http://www-106.ibm.com/developerworks/xml/library/x-starthere.html

Accessed 07/26/2003

“The W3C established ten primary design goals for XML:

1. XML must be easily usable over the internet.

2. XML must support a wide variety of applications.

3. XML must be compatible with SGML.

4. It must be easy to write programs that support XML documents.

5. The number of optional features in XML must be kept to an absolute minimum.

6. XML documents must be clear and easily understood by nonprogrammers.

7. The XML design should be prepared quickly.

8. the design of XML must be exact and concise.

9. XML documents should be easy to create.

10. Terseness in XML markup is of minimal importance.”

XML New Perspectives Patrick Carey Course technology 2002 p 1.07

“HTML is a language used for data presentation and formatting, XML’s

emphasis is on (reusable - FSH 07/26/2003) data content.”

XML New Perspectives, Patrick Carey, Course technology 2002 p 1.07

(3) What business problem does XML solve?

"XML has become the syntax of choice for newly designed document formats

across almost all computer platforms."

XML in a Nutshell 2nd Edition, Elliot Rusty Harold & W. Scott Means, O'reilly & Associates 2002

(It bridges the gap between diverse operating systems-FSH)

“XML can more easily perform some functions that HTML wasn’t created to do:

Tightly control document displays

Be flexible enough to describe different specific types of information

Convey information in a variety of media and formats

Define complex linking relationships between documents

Publish a single set of information across a variety of media” (Extremely portable- FSH)

XML for Dummies Second Edition, Ed Tittel Frank Boumphrey, Hungrey Minds Inc 2002 p27

“HTML is a language used for data presentation and formatting, XML’s

emphasis is on (reusable - FSH 07/26/2003) data content.”

XML New Perspectives, Patrick Carey, Course technology 2002 p 1.07

(4) Is XML a language or meta-language? Explain

“Although XML is sometimes referred to as a markup language, it is actually more of a meta-markup language because it is a markup language that is used to create other markup languages. Unlike HTML, which is an SGML application, XML should be considered a subset of SGML.”

XML New Perspectives Patrick Carey Course technology 2002 p 1.07

(5) What language was XML and HTML derived from?

SGML

(6) Why does XML need to be human and machine readable?

An XML document needs to be read (“parsed”) by an XML processor (“parser”)

To insure that it is well formed and valid (satisfied XML specifications for structure and syntax.) The data can then be read, manipulated, or modified by a individual (or XML application.)

(7) What are the three requirements for writing well formed XML?

“In XML, every start tag must have a corresponding end tag (unless it is an empty tag that takes special form, as described in the next item). Tags should be properly nested; that is, you can't have an open tag within the scope of some other tag and the corresponding end tag outside that scope.

If a tag is empty by its nature (in other words, the corresponding element can never contain any text), it must have a forward slash (/) before the closing greater than symbol (>) Such tags are the only tags that do not have corresponding end tags.

All attribute values without exception must be enclosed in quotes (either single quotes (‘) or double quotes ("")).

In fact, the preceding requirements are the only ones that you must satisfy to make your files well-formed XML.”

http://www.webreference.com/dlab/books/html/38-2.html

Accessed 07/29/2003 FSH

(8) What is the role of a DTD with XML?

The “Document Type Definition” comprises (or “defines”) what will be allowed (elements, attributes, etc.) to occur in the XML document that references it;

…the “rules”, as it were-FSH

(9) Write a very short DTD document

(This document should be named “test.dtd”)

<!ELEMENT my_name (name)>

<!ELEMENT name (first_name,last_name)>

<!ELEMENT first_name (#PCDATA)>

<!ELEMENT last_name (#PCDATA)>

Should be referenced by:

(This document should be named test.xml)

<?xml version="1.0" encoding="UTF-8" standalone="no"?>

<!DOCTYPE my_name SYSTEM “test.dtd">

<my_name>

<name>

<first_name>frederick</first_name>

<last_name>haggerty</last_name>

</name>

</my_name>

(10) What is the role of CSS with XML?

CSS gives us the ability to add "form to function”.

Whereas:

“HTML is a language used for data presentation and formatting, XML’s

emphasis is on (reusable - FSH 07/26/2003) data content.”

XML New Perspectives Patrick Carey Course technology 2002 p 1.07

CSS allows us to enhance the possible “presentation” capabilities of XML.

(11) Write very short CSS document?

I have provided three documents as follows:

This is the CSS (stylesheet named test.css) associated with test.xml

my_name {display:block; background-color:#C6EFF7; color:#000066; border:thin solid black; margin-top:20px; text-align:center; font-family:Arial; font-size:10pt; }

This document should be named “test.dtd”

<!ELEMENT my_name (name)>

<!ELEMENT name (first_name,last_name)>

<!ELEMENT first_name (#PCDATA)>

<!ELEMENT last_name (#PCDATA)>

text.dtd should be referenced by:

This document named test.xml

<?xml version="1.0" encoding="UTF-8" standalone="no"?>

<?xml-stylesheet type ="text/css" href="test.css"?>

<!DOCTYPE my_name SYSTEM "test.dtd">

<my_name>

<name>

<first_name>frederick</first_name>

<last_name>haggerty</last_name>

</name>

</my_name>

(12) What is the role of XSD with XML? (Think namespaces and datatypes)

“XSD (XML Schema Definition), a Recommendation of the World Wide Web Consortium (W3C), specifies how to formally describe the elements in an Extensible Markup Language (XML) document. This description can be used to verify that each item of content in a document adheres to the description of the element in which the content is to be placed.”

http://searchwebservices.techtarget.com/sDefinition/0,,sid26_gci831325,00.html

Accessed 07/28/2003 FSH

“A schema…defines what a given set of one or more XML documents can look like:

what elements they contain, and in what order, what their content might be, and what attributes these might contain.”

XML for the World Wide Web, Elizabeth Castro, Peachpit Press 2001

“XML Schemas express shared vocabularies and allow machines to carry out rules made by people. They provide a means for defining the structure, content and semantics of XML documents.”

http://www.perfectxml.com/XMLAcronyms.asp

Accessed 07/28/2003 FSH

(13) Write a very short XSD document

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

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified">

<xs:element name="my_name">

<xs:complexType>

<xs:sequence>

<xs:element name="name">

<xs:complexType>

<xs:sequence>

<xs:element name="first_name" type="xs:string"/>

<xs:element name="last_name" type="xs:string"/>

</xs:sequence>

</xs:complexType>

</xs:element>

</xs:sequence>

</xs:complexType>

</xs:element>

</xs:schema>

(14) Why are namespaces important to XSD?

"Namespaces have two purposes in XML:

1. To distinguish elements and attributes from different vocabularies with different meanings that happen to share the same name.

2. To group all related elements and attributes from a single XML application together so software can easily recognize them."

XML in a Nutshell 2nd Edition, Elliot Rusty Harold & W. Scott Means, O'reilly & Associates 2002 p60

"XML namespaces provide a simple method for qualifying element and attribute names used in Extensible Markup Language documents by associating them with namespaces identified by URI references."

http://www.w3.org/TR/REC-xml-names/

Accessed 07/28/2003 FSH

If other XML document(s) interact with mine, our schemas might contain duplicate names/words with conflicting rules/definitions; this would create a problem! We use namespaces to create (what Elizabeth Castro refers to as) a "superlabel". This allows the "words" in each XML document/schema to become unique/individual/distinct.

-FSH

(15) Compare and contrast DTDs with XSD

"DTDs have several disadvantages with respect written with XML Schema. First, DTDs are written in a syntax that little to do with XML, thus can not be parsed with an XML parser (a parser that parses XML content exclusively-FSH). Second, all declarations are global, which means you can't define two different elements with same name, even if they appear in separate contexts (see answer [#14] above- FSH). Finally, DTDs can not control what kind of information a given element or attribute can contain."

"XML schema ...written in XML itself, lets you define both global elements (that must be used the same way throughout the XML document) and local elements (that can have a particular meaning in a particular context).

XML schema contains a system of datatypes that let you specify what an element should contain (i.e. integer,

period of time)."

"In short, XML schema gives you much more control over the documents content."

XML for the World Wide Web, Elizabeth Castro, Peachpit Press 2001

(16) Compare and contrast CSS with XSLT

CSS (Cascading Style Sheets) in XML are not all that different than CSS in HTML except that some predefined elements and attributes that exist in HTML; notably <STYLE>, <LINK> elements and style, class attributes are meaningless in XML until they are assigned a definition.

"CSS in general serve the purpose of improving the expression (the way it is presented- FSH) of XML data

...for example font-size and family, the way the document flows...(etc.- FSH)"

Beginning XML Wrox Press David Hunter 2000 p61

(In XML this is a method)..."to separate (the XML) data from the way it is displayed." This is referred to as the "Content/Presentation Paradigm"

Beginning XML Wrox Press David Hunter 2000 p65

XSLT (Extensible Style sheet Language for Transformation) is a language that can be used to transform XML documents into any text format.

"XSLT and CSS provide complementary functionality - XLST can help you structure your pages in a wide number of formats, and CSS can balance this with easily modifiable media representations."

Beginning XML, David Hunter, Wrox Press 2000 p214

Lastly:

"XSLT does not replace CSS...XLST's primary domain is to provide transformation", (CSS enhances the results of this transformation-FSH)

Beginning XML, David Hunter, Wrox Press 2000 p132

(17) What is XSL or XSLT?

"XSLT, which stands for Extensible Stylesheet Language: Transformations, is a language which, according to the very first sentence in the specification (found at <http://www.w3.org/TR/xslt>), is primarily designed for transforming one XML document into another. However, XSLT is more than capable of transforming XML to HTML and many other text-based formats, so a more general definition might be as follows:XSLT is a language for transforming the structure of an XML document."

http://archive.devx.com/upload/free/bkchapters/xsltproref/31290102.asp

Accessed 07/29/2003 FSH

"In order to perform an XSLT transformation, you need at least three things: an XML document to transform, an XSLT style sheet, and an XSLT engine."

Beginning XML, David Hunter, Wrox Press 2000 p132

XSLT is an XML based language used to create style sheets. An XML engine (such as MSXML included in IE5 and higher-FSH) uses these style sheets to transform XML documents into other document types.

(18) What is XLink and XPointer?

"XLink (is) an attribute based syntax for hyperlnks between XML, and non-XML documents that provide the simple one-directional links familiar from HTML, multidrectional links between many documents, and links between documents to which you don't have write access."

XML in a Nutshell 2nd Edition, Elliot Rusty Harold & W. Scott Means, O'reilly & Associates 2002

"Xpointer (is) a syntax for URI fragment indentifier that selects particular parts of the XML document referred to by the URI - often used in conjunction with XLink."

XML in a Nutshell 2nd Edition, Elliot Rusty Harold & W. Scott Means, O'reilly & Associates 2002

Xlink allows XML documents to utilize hyperlinking that expands the possibilities thought of in the traditional HTML sense. Xpointers are designed to take you to specific locations within documents. XPointers can identify ID type attributes. If you want to link to an element that contains an ID attribute, the XPointer consists of the value of that attribute. Xpointers will also provide a method to point to a certain section within documents.-FSH

(19) What is RDF?

“Resource Description Framework, as its name implies, is a framework for describing and interchanging metadata. It is built on the following rules:

Resource is anything that can have a URI; this includes all the world's Web pages, as well as individual elements of an XML document.

PropertyType is a Resource that has a name and can be used as a property, for example Author or Title. In many cases, all we really care about is the name; but a PropertyType needs to be a resource so that it can have its own properties.

Property is the combination of a Resource, a PropertyType, and a value. An example would be: "The Author of http://www.textuality.com/RDF/Why.html is Tim Bray." The Value can just be a string, for example "Tim Bray" in the previous example, or it can be another resource.

RDF is designed to have the following characteristics:

Independence, Interchange, Scalability, PropertyTypes are Resources,

Values Can Be Resources, Properties Can Be Resources”

http://www.xml.com/pub/a/98/06/rdf.html

Tim Bray [Jan. 24, 2001]

Accessed 07/29/2003 FSH

(20) What is EAI? Why is XML useful in EAI?

“EAI is use of middleware to integrate the application programs, and legacy systems involved in an organization's critical business processes.”

http://www.hyperdictionary.com/dictionary/Enterprise+Application+Integration

Accessed 07/29/2003 FSH

Enterprise Application Integration. XML would be useful in this type of business model because it would ensure “applications and systems are integrated across an enterprise, improving information flows and streamlining business processes.”

http://www.datamirror.com/?src=overture

Accessed 07/29/2003 FSH

EAI can “automate critical aspects of the business process with a profound impact on service levels, profitability and communications.” This is often implemented as an application-to-application type structure.

http://www.staffware.com/landing/eai/?link=OvertureEAI

Accessed 07/29/2003 FSH

(21) Compare and contrast middleware with EAI

“Middleware is software that mediates between an application program and a network. It manages the interaction between disparate applications across the heterogeneous computing platforms. The Object Request Broker (ORB), software that manages communication between objects, is an example of a middleware program.”

http://www.hyperdictionary.com/computing/middleware

Accessed 07/29/2003 FSH

“EAI is use of middleware to integrate the application programs, databases, and legacy systems involved in an organization's critical business processes.”

http://www.hyperdictionary.com/dictionary/Enterprise+Application+Integration

Accessed 07/29/2003 FSH

(22) How does Microsoft use XML

"The Channel Definition Format (CDF) is a file format from Microsoft that lets you create a file that defines a Web "channel," which is a preselected Web site or group of related Web sites. To use the channel, a user needs to have the Microsoft Internet Explorer 4 or later browser. The CDF file identifies the Web page and subpages that the user sees after selecting a channel on the browser. The file may also identify subpages that may be selected from the main channel page. A channel developer for a Web site puts the CDF file on the Web server. A user who clicks on a channel (for example, from the Internet Explorer channel menu bar) is actually specifying the Uniform Resource Locator or Internet file name of the Channel Definition File that defines the channel.

The Channel Definition Format is an application of Extensible Markup Langugage (XML) that Microsoft is proposing as a standard way to describe a Web site channel. In Internet Explorer 5, the channel user implementation has been changed. The Channel Bar that formerly appeared automatically when Windows was started has been removed. Channels are now accessed as a special folder in the Favorites menu."

http://searchwebservices.techtarget.com/sDefinition/0,,sid26_gci213841,00.html

Accessed 07/29/2003 FSH

Microsoft also seems to be employing XML “data bases” (in such as applications as SQL) in much of the underlying foundation of the file/document sharing aspects of the (relatively new) .NET infrastructure.(FSH)

Example:

"MapPoint .NET XML Web Service

Microsoft MapPoint .NET is a hosted, programmable XML Web Service that allows you to integrate high-quality maps, driving directions, distance calculations, proximity searches, and other location intelligence into your applications, business processes, and Web sites."

(23) How does Sun use XML?

It would appear that Sun, having been unable to wrest from Microsoft the domination in “Office” related software by giving away “Star Office" (which incidentally loads a document as XML for processing) to the desktop community is reverting to the long held belief (along with Oracle) that “fat server thin client” is the future. They spearhead a consortium that is using XML (and their influence at W3C) to make a networking XML application that will essentially compete with Microsoft’s products.

That’s the way it looks to me.

I could be wrong.-FSH

“A posting from Michael Brauer <mailto:michael.brauer@sun.com> to the OASIS Open Office XML Format Technical Committee mailing list contains the OpenOffice.org XML file format specification and DTD files that Sun Microsystems, Inc. will contribute to the OASIS TC. The contribution will be discussed at the TC's first meeting on December 16, 2002. The XML specification consists of a 571-page OpenOffice.org XML File Format - Technical Reference Manual and 22 modularized XML DTD files. The design goal in the OpenOffice.org XML file format was to have a complete specification encompassing all OpenOffice.org components and to provide an open standard for office documents. The single XML format applies to a wide range of document types created by office tools. The specification is being made available to OASIS under a reciprocal Royalty-Free License, as explained in the communiqué.

A Late-Breaking News session at XML 2002 (December 10, 2002) feature the file format in a presentation by Daniel Vogelheim (Software Engineer, Sun Microsystems, Germany). In "XML For The Masses - An XML Based File Format for Office Documents" <http://www.xmlconference.org/xmlusa/2002/tuesday.asp> Daniel examined the design rationale behind the OpenOffice.org XML File Format and described uses of the format within and outside of its supporting applications.

Modularized DTD filenames: accelerator.dtd, chart.mod, datastyl.mod, defs.mod, dialog.dtd, drawing.mod, dtypes.mod, event.dtd, form.mod, image.dtd, menubar.dtd, meta.mod, nmspace.mod, office.dtd, office.mod, script.mod, settings.mod, statusbar.dtd, style.mod, table.mod, text.mod, toolbar.dtd

The goal of the OASIS Open Office XML Format TC is "to create an open, XML-based file format specification for office applications." On 2002-11-04 OASIS issued a Call for Participation in this new 'Open Office XML Format Technical Committee'. Michael Brauer (Sun Microsystems) will chair the TC. The proposed XML file format is to be "suitable for office documents containing text, spreadsheets, charts, and graphical components." It will be compatible XML v1.0 and W3C Namespaces. The file format will "retain high-level information suitable for editing the document and keep the document's content and layout information separate such that they can be processed independently of each other." For interoperability, it must be "friendly to transformations using XSLT or similar XML-based languages or tools. The design will borrow from similar, existing standards wherever possible and permitted. Since the OpenOffice.org XML format specification meets these criteria and has proven its value in real life, this TC will use it as the basis for its work. TC work will be done in two phases, each resulting in a Committee Specification that includes (1) a set of XML DTDs/schemas setting the vocabulary, constraints and semantics of the file format in question, and (2) a set of written specifications that describe the elements and attributes of the DTDs/schemas in plain English."”

http://xml.coverpages.org/ni2002-12-11-a.html

Accessed 07/29/2003 FSH

http://www.openoffice.org/

(24) What is UDDI, and why is it important?

UDDI The service discovery protocol for Web Services through which companies can find one another to conduct business. This standard was unveiled by Ariba, IBM, Microsoft, and 33 other companies in September 2000.

http://www.hyperdictionary.com/dictionary/Universal+Description%2c+Discovery%2

Accessed 07/29/2003 FSH

It would seem as though major companies with seemingly somewhat disparate and competitive backgrounds are seeking a common communication thread. This concept was unheard of in the 1990's and is even today revolutionary. The underlying method for these "high tech yellow pages" seems to be based in XML and the major contributors (SAP, MS, IBM (yes even Microsoft), etc.) involvement with an operation called OASIS which incorporates the newly evolving technology. This is a major step forward in inter-company cooperation, and ultimately the consuming public will reap its benefits.

(25) What are web services, SOAP, and WSDL, and how do they incorporate XML?

"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: an envelope that defines a framework for describing what is in a message and how to process it, a set of encoding rules for expressing instances of application-defined datatypes, and a convention for representing remote procedure calls and responses. SOAP can potentially be used in combination with a variety of other protocols..."

http://www.w3.org/TR/SOAP/

Accessed 07/29/2003 FSH

"SOAP is a lightweight and simple XML-based protocol that is designed to exchange structured and typed information on the Web. The purpose of SOAP is to enable rich and automated Web services based on a shared and open Web infrastructure. SOAP can be used in combination with a variety of existing Internet protocols and formats including HTTP, SMTP, and MIME and can support a wide range of applications from messaging systems to RPC."

http://msdn.microsoft.com/library/default.asp?url=/nhp/default.asp?contentid=28000523

Accessed 07/29/2003 FSH

"WSDL is an XML format for describing network services as a set of endpoints operating on messages containing either document-oriented or procedure-oriented information. The operations and messages are described abstractly, and then bound to a concrete network protocol and message format to define an endpoint. Related concrete endpoints are combined into abstract endpoints (services). WSDL is extensible to allow description of endpoints and their messages regardless of what message formats or network protocols are used to communicate, however, the only bindings described in this document describe how to use WSDL in conjunction with SOAP 1.1, HTTP GET/POST, and MIME."

<http://www.w3.org/TR/wsdl>

Accessed 07/29/2003 FSH

“'What is WSDL, NASSL and WDS?” WSDL (Web Services Description Language) is an XML-based specification schema for describing the operational information of a Web service such as interface and end points. WSDL defines XML grammar for describing contracts between a set of endpoints exchanging messages. Contracts provide documentation for distributed systems and serve as a recipe for automating the details involved in applications communication. WSDL may be used to design specifications to invoke and operate Web Services on the Internet. Using WSDL, Web Services can be enabled to access and invoke remote applications and databases. NASSL (Network Accessible Services Specification Language) was the IDL used on previous versions of the Web Services toolkit. The features of NASSL have been incorporated into WSDL. WSDL should now be used instead of NASSL. WDS (Well Defined Services) is an XML-based document schema for describing non-operational service information (service category, description, expiration date, etc.) and other business information (company name, SIC code, address, etc.) for using Web Services to enable e-business. Once UDDI is fully incorporated into a future version of the toolkit, many of the WDS categorization can be handled by the UDDI registry."

http://xml.coverpages.org/wsdl.html

Accessed 07/29/2003 FSH