XML_Session01.pps

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Extensible Markup Language

Session 1

Data interchange is essential to carry out business

transactions. However, organizations store data in disparate

formats, which makes the process of data interchange

complex and time-consuming.

Extensible Markup Language (XML) is a standard, simpleway of storing the data in a format that can be exchanged

across multiple systems across an enterprise. Providing an

insight into XML will benefit students as it is a standardtechnology to describe and define documents.

The course is applicable to students who want to create

well-formed XML documents. This course introduces

students to the fundamentals of XML and enable them to

effectively use XML as a markup language to develop Web

applications.

Rationale


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Session 1

In this session, you will learn to:

Identify the need for XML as a standard data interchange

format

Identify the structure of XML documents

Objectives


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Session 1

Traditionally, preprinted formats were used to exchange

information between businesses.

Need for a more effective way of communicating and

processing business data led to the emergence of Electronic

Data Interchange (EDI).EDI refers to the process of exchanging documents in a

standard format between two computer systems.

EDI has the following limitations:

Rigid transaction set

Fixed business rulesHigh costs

Slow pace of standards evolution

Getting Started with XML


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Session 1

XML is a text-based markup language that enables storage

of data in a structured format.

XML is a cross-platform, hardware and software

independent markup language that enables structured data

transfer between heterogeneous systems.XML is used as a common data interchange format in a

number of applications.

Let us understand the usage of XML with the help of the

diagram.

Introducing XML


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Session 1

Introducing XML (Contd.)

Web Application

Web Services

.

XML

Windows Application

Mobile Application

SQL Server

DB2 OracleAccess

Data Sources


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Session 1

Web Architecture Using XML

In a traditional Web architecture, a client sends a request to

the server in a pre-defined format and receives the response

accordingly.

The advantage of using XML in the Web architecture is that the

structure of the request can be obtained from the server at run

time.

XML can encode non-relational data as well as relational data

structure.



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Session 1

Web Architecture Using XML (Contd.)

The following figure depicts the XML Web architecture.





Session 1

Difference Between SGML, HTML, and XML

Standard Generalized Markup Language (SGML) allows

documents to describe their grammar by specifying the tag set

used in the document and the structural relationship that these

tags represent.

Hypertext Markup Language (HTML) is used for datapresentation.

XML is used for data description and definition.





Session 1

Difference Between SGML, HTML, and XML (Contd.)


SGML HTML XML

Extensibility

Structure

Validation

BrowserDependency

Cost/Benefit

Low High Low

Poor Good Medium

Yes Yes Yes

Yes No Yes

Yes No Yes


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Session 1

Advantages of XML

Some of the advantages of XML are:

Domain-specific vocabulary

Data interchange

Smart searches

Granular updates

User-selected view of data

Message transformation



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Session 1

Advantages of XML



Data interchange

Smart searches

Granular updates




In HTML, only the predefined tags can be

used.

In XML, you can create new tags based

on the requirements of the application.

Various languages such as MathML and

WML have been derived from XML.


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Session 1

Advantages of XML



Data interchange

Smart searches

Granular updates




XML produces files that are

unambiguous, easy to generate,

and easy to read.XML provides a structure to

store data in textual format,

which can then be used as a

standard format or protocol for

data interchange.


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Session 1

Advantages of XML



Data interchange

Smart searches

Granular updates




The flexibility to create user-defined

tags in XML enables creation ofsmart search engines.

You can differentiate whether you

want do to search based on a text or

on a tag, which enables the browser

to perform a focused search and

return precise information that

matches the search query.


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Session 1

Advantages of XML



Data interchange

Smart searches

Granular updates




Document updates in HTML

are slow as the entire

document needs to be

refreshed from the server.

Document updates in XML are

faster as only the changed

content needs to be

downloaded.


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Session 1

Advantages of XML



Data interchange

Smart searches

Granular updates




In HTML, you need to create

separate HTML pages to

display the same information

in different formats while XML

concentrates on data and not

on its presentation.

HTML does not allow

conditional formatting of a

document while in XML

conditional formatting is

possible.


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Session 1

Advantages of XML



Data interchange

Smart searches

Granular updates




In XML, a message can be stored in

the form of a document, object data,

or data from a database.

XML design provides flexibility while

storing data as it does not imposeany restriction on the field size and

the order in which the data is stored.


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Future of XML

The future uses of XML can be summarized as:

XML will be widely used in e-commerce.

XML will have a huge core market in the form of Business to

Business (B2B).

XML will be used for mobile devices due to its ability to easilyconvert into the appropriate format for any device.

XML will be used to solve communication problems in EDI and

Enterprise Application Integration (EAI) as it provides

interoperability between disparate applications.



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Session 1

W3C is responsible for the development of Web

specifications that describe communication protocols and

technologies for the Web.

Due to the flexibility for customization in XML, W3C has laid

down these rules that need to be followed by all XML

vendors:

XML must be directly usable over the Internet.

XML must support a wide variety of applications.

XML must be compatible with SGML.

XML should have absolute minimum number of optionalfeatures, ideally zero.

XML documents must be human legible and clear.

XML design must be formal and concise.

XML documents must adhere to a set of constraints called full

normalization.

Introducing W3C


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Session 1

An XML application is considered well designed if it is

robust and scalable.

To design a robust and scalable XML application, the

following steps need to be performed:

1. Create an information model.2. Identify the required components of the XML document.

3. Create the XML document.

Identifying the Structure of XML Documents


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An information model is a description of the information

used in an organization.

Information modeling helps identify:

Objects involved in an application

Properties of the objectsRelationships among objects

XML provides the following additional capabilities to

information modeling:

Heterogeneity

ExtensibilityFlexibility

Information Modeling

Each record can contain different data

fields.New data types can be added

whenever required.Data fields can vary in size andconfiguration between instances.


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Session 1

Types of information models that can be created for an XML

application are:

Static model: Helps define all the objects in an application and

the relationships among them.

Dynamic model: Helps to determine the information flow of an

application in the form of messages.

Information Modeling (Contd.)


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Session 1

The various components of an XML document used for

representing data in a hierarchical order are:

Processing Instruction (PI)

Tags

Elements

Content

Attributes

Entities

Comments

Components of an XML Document


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Toys

100

The price of this toy

is < 200

Components of an XML Document (Contd.)


Provides information on how

the XML file should be

processed.


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Toys

100


is < 200


Root Element

Contains all other elements

in the document.


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Toys

100


is < 200


Comments

Are statements used to

explain the XML code.


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Toys

100


is < 200


Child Elements

Are the basic units used to

identify and describe data inXML.


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Toys

100


is < 200


Attributes

Provide additional

information about theelements for which they are

declared.


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Session 1

Toys

100


is < 200


Entities

Is a set of information that

can be used by specifying a

single name.


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Session 1

The rules that govern the creation of a well-formed XML

document:

Every start tag must have an end tag.

Empty tags must be closed using a forward slash (/).

All attribute values must be given in double quotation marks.

Tags must have proper nesting.

XML tags are case sensitive.

Identifying the Rules for Creating XML Documents


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Session 1

Problem Statement:

CyberShoppe, Inc. sells toys and books in the United States. It

has three branches in different parts of the country. Currently,

the three branches maintain data on their local computer

systems. The IT manager at CyberShoppe has identified that a

centralized data repository on the products sold through itse-commerce site is required. The data from all branches must

be collated and housed in a centralized location. This data

must be made available to the Accounts and Sales sections at

the individual branches, regardless of the hardware and

software platforms being used at the branches.

In addition, the sales personnel require access to the datausing palmtops and cellular phones. The product details of

CyberShoppe consist of the product name, a brief description,

the price, and the available quantity on hand. A product ID

uniquely identifies each product.

Demo: Creating an XML Document


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Session 1

Bob is the EDP head of an organization that manufactures

and sells hardware parts. The organization has presence in

all the major cities of the United States. At present, all

branch offices maintain their data locally. Bob wants to

centralize the repository of data in his organization. Data

from all the branch offices needs to be collated and stored ina centralized location. Data pertaining to a branch should be

available only to that branch office. However, the head office

should be able to access all the data.

Practice Questions


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Session 1

In addition, Bob also wants that the sales personnel should

be able to access sales data from mobile devices, such as

palmtops and mobile phones. This sales information should

have a brief description of the product, the price, and the

available inventory. Using which of the following markup

languages can Bob achieve the preceding goals?a. HTML

b. XML

c. SGML

d. EDI

Answer:

b. XML

Practice Questions (Contd.)


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Session 1

Which of the following statement is NOT true about

information modeling?

a. Information Modeling is used to understand the structure and

meaning of information that will be stored in XML documents.

b. Information Modeling helps you identify the objects involved in

an application, the properties of the objects, and therelationships among them.

c. In an Information Model, each record can contain different data

fields.

d. An information model imposes restrictions on data.

Answer:

d. An information model imposes restrictions on data.

Practice Questions

ibl k


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Session 1

Which one of the following statements is true about XML?

a. XML is a text-based markup language that provides predefined

tags to store data.

b. XML is a platform-neutral data interchange format.

c. XML requires VAN for data interchange.

d. XML allows you to specify data formatting instructions.

Answer:

b. XML is a platform-neutral data interchange format.

Practice Questions

ibl k


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Session 1

Which one of the following is a disadvantage of traditional

EDI?

a. It provides fixed transaction sets.

b. It increases the communication lag time between an agency

and a customer.

c. It increases data entry errors.

d. It increases the time taken to process orders.

Answer:

a. It provides fixed transaction sets.

Practice Questions

E t ibl M k L


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Session 1

In this session, you learned that:

EDI refers to the process of exchanging documents in a

standard format between two computer systems.

XML is a text-based markup language that enables you to

store data in a structured format by using meaningful tags.

Using XML in Web architecture enables loose couplingbetween the server application and the client application.

XML has the following advantages:


Data interchange

Smart searchesGranular updates



Summary

E t ibl M k L


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Session 1

In future, XML will be widely used in:

E-commerce

B2B services

Mobile services

EDI and EAI

XML was defined by W3C to ensure that structured data isuniform and independent of vendors and applications.

In XML, an information model is used to understand the

structure and meaning of information that will be stored in XML

documents.

You can create static, dynamic, or a combination of both theseinformation models for an XML application.

A static information model helps you define all the objects in an

application and the relationships among them.

Summary (Contd.)

E t ibl M k L


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In a dynamic model, data flow diagrams and process diagrams

are used to determine the flow of information.

An XML document consists of:


Tags

ElementsContent

Attributes

Entities

Comments

Summary (Contd.)