1 Copyright © [2010]. Roger L. Costello. All Rights Reserved. XML Schema 1.1 for Managers Roger L....

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Copyright © [2010]. Roger L. Costello. All Rights Reserved.

XML Schema 1.1 for Managers

Roger L. Costellohttp://www.xfront.com

3 December, 2012

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Purpose

• The purpose of this tutorial is to give an overview of the new features of XML Schema 1.1 without getting into its syntax.

• It is targeted to managers.

• I show how these new technical features can benefit your business.

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Your 1.0 Schemas will still work

An XML document conforming to a 1.0 schema can be validated using a 1.1 validator, but an XML document conforming to a 1.1 schema might not validate using a 1.0 validator.

XML Schema 1.0

XML Schema 1.1

XML Schema 1.1 is a superset of XML Schema 1.0

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XML Schema 1.1 Validators

• The schema-aware version of SAXON (version 9.3 or later) supports the full XML Schema 1.1 specification: http://www.saxonica.com/

• Apache XERCES supports XML Schema 1.1: http://xerces.apache.org/xerces2-j/

• You can create XML Schema 1.1 schemas today!

5


Status

• XML Schema 1.1 became a standard on April 5, 2012 (the W3C calls it a “recommendation” not a standard, but they are the same)

6


Technology Stack

XML

Namespaces

XPath

XML Schema 1.0

XML Schema 1.1

Each technology assumes you know the technologies beneath it.

7


Review:Purpose of

XML Schemas

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Two uses of XML

XML as a temporary transport vehicle:– As soon a the XML gets to its

destination the data is extracted and put into a permanent storage mechanism (such as a database).

– Applications operate on the data in the permanent storage.

XML as permanent storage:– Applications operate

directly on the XML.

XML

app

app

appXML XML

"shred"

app

app

app

ship the XML

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XML as a temporary transport vehicle

XML XML

"shred"

app

app

app

ship the XML

An XML Schema can be used as a contract between the sender and the receiver: "Here's the information we agree to exchange, and the format of the information."

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XML as permanent storage

XML

app

app

app

XML

Rob Sally Pete Jill Anthony

Often occurring in the form of a workflow:

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XML as permanent storage(cont.)

XML

app1 app2 app3 app4

Each application does a "unit of work." It is desirable, after each unit of work, to assess the system. XML Schemas can be used to check each application's output.

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Check the information–validate that no rules are being broken.

Do some work.

Then validate that no rules have been broken (as a result of the work), i.e., check that you’re still on track.

Then do another unit of work.

Then validate again.

Then do another unit of work.

Then validate again.

And so forth.

I envision systems working like this:

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Rules

• We live in a world of rules:– Driving: we follow the rules of the road– Queues: we form lines at banks and in the

checkout lanes at the supermarket– Taxes: accountants spend lots of time each year

learning the new tax rules– Laws: our legal system enforces societies' laws

• Rules guide our actions.

• Rules let us know if we are on or off track.

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Rules are Important

All enterprise work as it grows toward perfection becomes rule-based

Roger Costello and Bob Wilson

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XML Schema = Rules

• XML Schemas is all about expressing rules:– rules about what data is allowed– rules about how the data must be organized– rules about the relationships between data

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Example: My Vacation

<Vacation> <Trip segment="1" mode="air"> <Transportation>airplane</Transportation> </Trip> <Trip segment="2" mode="water"> <Transportation>boat</Transportation> </Trip> <Trip segment="3" mode="ground"> <Transportation>car</Transportation> </Trip></Vacation>

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Validate

<Vacation> <Segment id="1" mode="air"> <Transportation>airplane</Transportation> </Segment> <Segment id="2" mode="water"> <Transportation>boat</Transportation> </Segment> <Segment id="3" mode="ground"> <Transportation>car</Transportation> </Segment></Vacation>

Rule 1: A vacation has segments.Rule 2: Each segment is uniquely identified.Rule 3: There are three modes of transportation: air, water, ground.Rule 4: Each segment has a mode of transportation.Rule 5: Each segment must identify the specific mode used.

XML Schema

Validate the XMLdocument againstthe XML Schema

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Desirable Rules

mode Transportation

air airplane,hot-air balloon

water boat,hovercraft

ground car,bicycle

Rule: if mode = air thentransportation must be either airplane or hot-airballoon.Similar rules for water and ground.

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XML Schema 1.0 cannot detect this error

<Segment id="1" mode="air"> <Transportation>boat</Transportation></Segment>

These are inconsistent.Error!

Why can’t the error be detected using XML Schema 1.0?Answer: Because the rule on the preceding slide cannot be expressed.

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XML Schema 1.1

• Much more powerful than 1.0

• Can express many more rules (The rule on the preceding slide can be expressed!)

• Let's see the new features that 1.1 provides …

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New Feature:Express Business Policies

and Rulesusing Assertions

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Example Policy

Level 1 managers may sign off on purchase requests that do not exceed $10K. Level 1 managers may sign off on purchase requests that do not exceed $10K.

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This doesn't conform to company policy

<purchase-request> <item>Widget</item> <cost>15000</cost> <signatureAuthority>Level 1</signatureAuthority></purchase-request>

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Validate

XML Schema

XML SchemaValidator

invalid!

<purchase-request> <item>Widget</item> <cost>15000</cost> <signatureAuthority> Level 1 </signatureAuthority></purchase-request>

Level 1 managers may sign off on purchase requests that do not exceed $10K.

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XML Schema 1.0

• With XML Schema 1.0 business policies and rules could not be expressed. – The policy rule on the previous slides could not be

expressed.

• Consequence: developers buried policies and rules in procedural code.

Javaprogram


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Disadvantage #1 of Buried Policies and Rules

Javaprogram

Policy, expressed in Java code Business

Person

I don't understand Java. I can't

change the policy. Argh!

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Difficult to change policies and rules.

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Javaprogram

Policy, expressed in Java code

Manager

How much can I sign

off on?

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The policies and rules are expressed in code instructions and are less visible – perhaps only the programmer knows the rules.

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XML Schema 1.1

• In XML Schema 1.1 policies and rules can be expressed.

• Policies and rules are declaratively expressed.

• Consequence: - Policies and rules can be easily changed- Policies and rules are transparent

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Example Business Rule


No paragraph may have a security classification higher than the document's classification.

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top-secret is higher than secret is higher than confidential is higher than unclassified

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Example Document

<Document classification="secret"> <Para classification="unclassified"> ... </Para> <Para classification="secret"> ... </Para> <Para classification="unclassified"> ... </Para> <Para classification="secret"> ... </Para></Document>

Ensure that no <Para> element has a classification higher than the <Document> element's classification

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XML Schema 1.0 versusXML Schema 1.1

• In XML Schema 1.0 you cannot express the rule on the previous slide.

• In XML Schema 1.1 you can express it.

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Grammar checks

Business rule checks

XML Schema 1.0

XML Schema 1.1

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XML Schema 1.0 versusXML Schema 1.1

• With XML Schema 1.0 you can express grammar (syntax) constraints, e.g., this markup should occur in this order, that data should be a date, and so forth.

• With XML Schema 1.1 you can still express grammar constraints but you can also express data relationships (business rules), e.g., the classification value here must be less than the classification value there.

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New Feature

assertion

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Express Policies and Rules using Assertions

Policies and rules are expressed in XML Schema 1.1 using assertions, e.g.,

Assertion: Level 1 managers may sign off on purchase requests that do not exceed $10K.

Assertion: No paragraph may have a security classification higher than the document's classification.

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Review

• We've examined the first new feature in XML Schema 1.1, the ability to express policies and rules using assertions.

• This feature is a big benefit to businesses: now businesses can declaratively express their policies and rules in XML Schemas rather than burying them in procedural code.

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New Feature:Creating Department-Specific

Data using Conditional Type Alternatives

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Example of Conditional Content


For each employee store this data: name, date of hire, employee number, and emergency contact telephone number.

Human Resources (HR) Department:

Level 1 managers may sign off on purchase requests that do not exceed $10K. For each employee store this data: name, areas of expertise, and current project.

Information Technology (IT) Department:

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Content varies, depending on dept.

<Employee dept="HR">

</Employee>

<Name>John Doe</Name><Hire-Date>2000-01-01</Hire-Date> <Employee-Num>123</Employee-Num> <Emergency-Contact>617-123-4567</Emergency-Contact>

<Employee dept="IT">

</Employee>

<Name>John Doe</Name><Expertise>XML, XML Schema</Expertise><Project>upgrade xyz interface</Project>

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<Employee dept="_________">

</Employee>

If it's HR then the content mustbe an HR type. If it's IT then the content must be an IT type.

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Conditional Content

The content of Employee is conditional to the value of dept.

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Example #2

<Publication kind="book">

</Publication>

<Title>Origin of Wealth</Title><Author>Eric D. Beinhocker</Author> <Date>2006</Date> <ISBN>1-57851-777-X</ISBN> <Publisher>Harvard Business School Press</Publisher>

<Publication kind="magazine">

</Publication>

<Genre>Scientific</Genre><Circulation>733,000</Circulation><Founded>1845-08-28</Founded>

The content of Publication depends on the kind of publication.

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<Publication kind="_________">

</Publication>

If it's magazine then the content mustbe a Magazine type. If it's book then the content must be a Book type.

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Conditional Content

The content of Publication is conditional to the value of kind.

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New Feature

alternative

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Express Conditional Content using Alternative

Conditional content is expressed in XML Schema 1.1 using alternatives, e.g.,

Alternative: if kind="magazine" then the content is a Magazine type.

Alternative: if kind="book" then the content is a Book type.

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Review

• We've examined two new features in XML Schema 1.1:– the ability to express policies and rules using

assertions– the ability to express conditional content using

alternatives

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New Feature:Expressing Business-wide

Attributes using Schema-wide Attributes

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A nice feature of HTML

These attributes can be used with any HTML element

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HTML has a set of attributes that can be used throughout the document. That's nice.

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Schema-wide Attributes

• In XML Schema 1.1 you can create a set of attributes and identify them as schema-wide, which means that they apply to every element in the schema document.

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In XML Schema 1.0 if every element is to have, say, a "title" attribute then a title attribute declaration must be repeated on every element. That's not nice (and it's error prone).

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New Feature

defaultAttributes

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Express Schema-wide Attributes using defaultAttributes

Schema-wide attributes are expressed in XML Schema 1.1 using defaultAttributes, e.g.,

defaultAttributes: these attributes apply throughout the schema document: class, id, title.

58


Review

• We've examined three new features in XML Schema 1.1:– the ability to express policies and rules using


alternatives– the ability to define schema-wide attributes

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New Feature: Enable Business Change

usingOpen Content

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U.S. Constitution

• Within the U.S. Constitution it describes how it can be changed.

• Our forefathers recognized that the world changes, and if the constitution doesn't adapt then it will ossify and be useless.

• So they built into the Constitution mechanisms for how it can be changed.

See section 3.1 of the following paper for a fascinating description of how the U.S. Constitution has mechanisms for changing itself:http://www.microfinance.com/English/Papers/Meta-rules.pdf

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Open Content

• XML Schemas that can't adapt to a changing world will ossify and be useless.

• Open content is a mechanism for enabling schemas to change.

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Book Seller Example

• You've coordinated with your clients and agreed to provide them with this information about each book:

Title, Author, Date, ISBN, Publisher

You create an XML Schema to express this.

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Example (cont.)

• Time passes … some clients request this additional information: - number of pages - binding (hardcover or softcover)And they want this information NOW!

• Your schema working group meets quarterly. Updates to support this new information are months away.

64


Example (cont.)

• By designing your schemas with open content you will be able to add the requested new information to XML instance documents without waiting for the next quarterly schema meeting.

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Example (cont.)

<Book> <Title>The Origin of Wealth</Title> <Author>Eric D. Beinhocker</Author> <NumPages>527</NumPages> <Date>2006</Date> <ISBN>1-57851-777-X</ISBN> <Publisher>Harvard Business School Press</Publisher> <Binding>Hardcover</Binding></Book>

Book Schemawith

Open Content

create XML instance

527

Hardcoveraddnewinfo

deliver toclients

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Example (concluded)

• The new data is delivered to the clients in a timely fashion.

• At the next quarterly meeting the XML Schema is updated: the information provided for each book is title, author, date, ISBN, publisher and numPages, binding.

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New Feature

openContent

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Express Schema-wide Attributes using openContent

Change is enabled in XML Schema 1.1 using openContent, e.g.,

openContent: permit new (client-requested) data to be interleaved among the standardized data.

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Review

• We've examined four new features in XML Schema 1.1:– the ability to express policies and rules using


alternatives– the ability to define schema-wide attributes– the ability to facilitate change using open content

70


New Feature:Enabling Departments to Customize Corporate Data

using override and error

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Wish I could customize …

• Oftentimes I've used a tool and thought, "Boy, if only I could open up this tool and make a few tweaks, then it would be perfect for my needs."

• Regrettably the tool is not modifiable and so I'm stuck using something that's not quite what I need.

• That said, using the tool is a lot better than creating a custom tool from scratch.

72


Unchangeable schemas can be customized!

• XML Schema 1.1 provides two mechanisms for customizing another schema without modifying it:– override– error

73


Override

meeting- start time- end time- room number

override meetingwith this content:- track id- speaker- room capacity

reuse

This schema reuses the corporate schema, but customizes "meeting" with the data that is particular to conference meetings.

Office Meeting

Conference Meeting

Corporate schema, can't be changed.

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How to change an unchangeable schema

Schema 1(read-only)

Schema 2

reuse

Schema 2 overrides items in Schema 1

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<Employee dept="_________">

</Employee>

If it's HR then the content mustbe an HR type. If it's IT then the content must be an IT type.

Corporate schema specifies this

Recall this earlier example

76


HR Department

The HR department wants to reuse the corporate schema, but prohibit IT content:

CorporateSchema

HRSchema

reuse <Employee dept="_________">

</Employee>

If dept="IT" then error

Generate anerror if deptis accidentallyassigned IT.

77


New Feature

override

78


New Feature

error

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Enable Customization usingoverride and error

Enabling customization is expressed in XML Schema 1.1 using override and error, e.g.,

override: replace items in the corporate schema with your own data (and without changing the corporate schema).

error: disallow the use of certain items in the corporate schema.

80


Review

• We've examined five new features in XML Schema 1.1:– the ability to express policies and rules using


alternatives– the ability to define schema-wide attributes– the ability to facilitate change using open content– the ability to customize schemas that ordinarily are

unchangeable, using override and error

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New Feature:Enabling Dissemination of

New Announcementsusing

inherited attributes

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<Merchandise discount="10%">

</Merchandise>

Want this discount information to be visible (disseminated) throughout the document

<Coats> …</Coats><Shirts> …</Shirts<Pants> …</Pants

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i.e., want this discount attribute to be "inherited"

<Merchandise discount="10%">

</Merchandise>

<Coats> …</Coats><Shirts> …</Shirts><Pants> …</Pants>

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<Contract language="FR">

</Contract>

Want this language information to be visible (disseminated) throughout the document

<Foreign-Release> …</Foreign-Release><State-Department> …</State-Department><Legal> …</Legal>

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<Contract language="FR">

</Contract>

i.e., want this language attribute to be "inherited"

<Foreign-Release> …</Foreign-Release><State-Department> …</State-Department><Legal> …</Legal>

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New Feature

inheritable

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Enable Information Dissemination using inheritable attributes

Enabling the dissemination of information is expressed in XML Schema 1.1 using inheritable attributes, e.g.,

inheritable: this attribute can be viewed and used from here on in.

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Review

• We've examined six new features in XML Schema 1.1:– the ability to express policies and rules using assertions

– the ability to express conditional content using alternatives

– the ability to define schema-wide attributes

– the ability to facilitate change using open content

– the ability to customize schemas that ordinarily are unchangeable, using override and error

– the ability to disseminate information within a document using inheritable attributes

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New Feature:Enabling User-Friendly

Arrangement of Informationusing "all"

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Camera Lens

The camera comes with a 37-155mm zoom lens

that has an f-stop of 4.8-11.7

The camera comes with a lens that has an f-stop

of 4.8-11.7 and is a 37-155mm zoom

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Does Order Really Matter?

<Camera-Lens> <f-stop>4.8-11.7</f-stop> <focal-length>37-155mm zoom</focal-length></Camera-Lens>

<Camera-Lens> <focal-length>37-155mm zoom</focal-length> <f-stop>4.8-11.7</f-stop></Camera-Lens>

-- versus --

92


Does Order Really Matter?

Probably not. To be user-friendly, allow both orders.

93


Any Order

• XML Schema 1.0 was pretty controlling in terms of the order of data.

• XML Schema 1.1 is much less controlling; schemas can be designed to allow the data to be arranged in any order.

94


New Feature

all

Note: "all" is found in XML Schema 1.0, but it did not permit elements with maxOccurs of 2 or more. XML Schema 1.1 does not have this restriction.

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Enable a user-friendly arrangement of information

using "all"

Enabling information to be expressed in any order is accomplished in XML Schema 1.1 using the "all" element, e.g.,

all: provide the f-stop and the focal-length of the camera lens in an order that is useful to you.

96


Review

• We've examined seven new features in XML Schema 1.1:– the ability to express policies and rules using assertions

– the ability to express conditional content using alternatives

– the ability to define schema-wide attributes

– the ability to facilitate change using open content

– the ability to customize schemas that ordinarily are unchangeable, using override and error

– the ability to disseminate information within a document using inheritable attributes

– the ability to present the information in a user-friendly order, using the "all" element

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Other New Features

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The many names of "subway"

• There are different ways of saying "I took the subway into town"– In Boston we say "I took the T into town"– In D.C. they say "I took the metro into town"– In London they say "I took the tube into town"– In Chicago they say "I took the L into town"

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Substitution

• XML Schema 1.1 enables you to express "T can be substituted for either metro or tube or L"

T

metro tube

substitutable for substitutable for

L

substitutable for

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Multiple Identifiers

My SSN is …My employee # is…

My driver's license # is …

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Multiple ID values

• XML Schema 1.1 enables you to associate multiple ID values to an element.

Stereo model-number="…" serial-number="…"

102


Symbol for the decimal point in U.S.A. versus France

15.7 (USA)

15,7 (France)

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What's the symbol for the decimal point in XML Schema 1.1?

15.7

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What's the symbol for the decimal point in XML Schema 1.1?

Isn't that unfair to the folks in France?

15.7

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Vendor-unique Extensions

• XML Schema 1.1 allows vendors to extend the language.

• Thus a vendor may create a new decimal datatype (French:decimal) with "," as the decimal point.

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Other new datatypes

• anyAtomicType: the anyAtomicType is the union of the values of all the primitive types (string + integer + boolean + …)

• dateTimeStamp: a dateTimeStamp value is a date plus time plus timezone

• yearMonthDuration: a yearMonthDuration value is a duration consisting of years and months

• dayTimeDuration: a dayTimeDuration value is a duration consisting of days and time

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Summary

• XML Schema 1.1 has lots of powerful new features.

• I hope this tutorial has convinced you that these new features can benefit your business.

• I recommend switching to XML Schema 1.1 as soon as possible.

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