Xml session01

Extensible Markup Language
Rationale

• 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, simple
way 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 standard
technology 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.

Ver. 1.0 Session 1 Slide 1 of 41

Objectives

In this session, you will learn to:
Identify the need for XML as a standard data interchange
format
Identify the structure of XML documents


Getting Started with XML

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 rules
High costs
Slow pace of standards evolution


Introducing XML

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 (Contd.)

.

Mobile Application Web Services

Windows Application

Web Application

XML

DB2 Oracle
SQL Server Access
Data Sources



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.



Web Architecture Using XML (Contd.)
The following figure depicts the XML Web architecture.



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 data
presentation.
XML is used for data description and definition.



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

SGML HTML XML
Extensibility
Yes Yes Yes

Structure
Yes No Yes

Validation Yes No Yes

Browser Low High Low
Dependency
Cost/Benefit Poor Good Medium



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



Advantages of XML
 Domain-specific vocabulary In HTML, only the predefined tags can
 Data interchange be used.

 Smart searches In XML, you can create new tags based
on the requirements of the application.
 Granular updates
Various languages such as MathML and
 User-selected view of data
WML have been derived from XML.
 Message transformation



Advantages of XML
 Domain-specific vocabulary
 Data interchange XML produces files that are
unambiguous, easy to generate,
 Smart searches
and easy to read.
XML provides a structure to
 User-selected view of data store data in textual format,
 Message transformation which can then be used as a
standard format or protocol for
data interchange.



Advantages of XML
 Data interchange
 Smart searches  The flexibility to create user-defined
tags in XML enables creation of
smart search engines.
 You can differentiate whether you
 Message transformation 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.



Advantages of XML
 Smart searches
 Granular updates  Document updates in HTML
are slow as the entire
 User-selected view of data document needs to be
 Message transformation refreshed from the server.
 Document updates in XML are
faster as only the changed
content needs to be
downloaded.



Advantages of XML
 Smart searches
 User-selected view of data In HTML, you need to create
separate HTML pages to
 Message transformation 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.



Advantages of XML
 Smart searches
 Message transformation  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 impose
any restriction on the field size and
the order in which the data is stored.



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 easily
convert 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.


Introducing W3C

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 optional
features, 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.

Identifying the Structure of XML Documents

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.


Information Modeling

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 objects
Relationships among objects
XML provides the following additional capabilities to
information modeling:
a Heterogeneity Each record can contain different data
fields.
 New data types can be added
a Extensibility
 whenever required. in size and
Data fields can vary
a Flexibility configuration between instances.


Information Modeling (Contd.)

Types of information models that can be created for an XML
application are:
a Static model: Helps define all the objects in an application and
the relationships among them.
a Dynamic model: Helps to determine the information flow of an
application in the form of messages.


Components of an XML Document

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 (Contd.)

<?xml version=“1.0” encoding=“UTF-8”?>
<STOREDATA> Processing Instruction (PI)

 Provides information on how
the XML file should be
<STORE STOREID=“S101”> processed.
<PRODUCTNAME>Toys</PRODUCTNAME>

<QUANTITY>100</QUANTITY>
<DISPLAY>The price of this toy
is < 200 </DISPLAY>
</STORE>
</STOREDATA>

<STOREDATA>
 Tags

<STORE STOREID=“S101”> Is a means of identifying
<PRODUCTNAME>Toys</PRODUCTNAME> data. Tags consist of start
tag and end tag.
is < 200 </DISPLAY>
</STORE>
</STOREDATA>

<STOREDATA>
Root Element

Contains all other elements
<STORE STOREID=“S101”> in the document.

is < 200 </DISPLAY>
</STORE>
</STOREDATA>

<STOREDATA>
 Comments
<STORE STOREID=“S101”>
Are statements used to
<PRODUCTNAME>Toys</PRODUCTNAME> explain the XML code.

is < 200 </DISPLAY>
</STORE>
</STOREDATA>


<STOREDATA>
<STORE STOREID=“S101”> Child Elements
<PRODUCTNAME>Toys</PRODUCTNAME> Are the basic units used to
identify and describe data in
<QUANTITY>100</QUANTITY> XML.
is < 200 </DISPLAY>
</STORE>
</STOREDATA>



<STOREDATA>
<STORE STOREID=“S101”> Attributes
Provide additional
information about the
elements for which they are
<DISPLAY>The price of this toy declared.
is < 200 </DISPLAY>
</STORE>
</STOREDATA>



<STOREDATA>
<PRODUCTNAME>Toys</PRODUCTNAME> Content
Refers to the information
<QUANTITY>100</QUANTITY> represented by the elements
<DISPLAY>The price of this toy of an XML document. An
is < 200 </DISPLAY> element can contain:

</STORE> • Character or data content
</STOREDATA> • Element content
• Combination or mixed
content



<STOREDATA>

<QUANTITY>100</QUANTITY> Entities
<DISPLAY>The price of this toy Is a set of information that
is < 200 </DISPLAY> can be used by specifying a
single name.
</STORE>
</STOREDATA>


Identifying the Rules for Creating XML Documents

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.


Demo: Creating an XML Document

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 its
e-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 data
using 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.


Practice Questions

Consider the following statement:
<?xml version="1.0" encoding= "UTF-8"?>
Which component of an XML document does the preceding
statement represent?
a. Element
b. Content
c. Entity
d. Processing Instruction

Answer:
d. Processing Instruction


Practice Questions

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
in a 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 (Contd.)

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

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 the
relationships 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

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

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.


Summary

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 coupling
between the server application and the client application.
XML has the following advantages:
Domain‑specific vocabulary
Data interchange
Smart searches
Granular updates
User‑selected view of data
Message transformation


Summary (Contd.)

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 is
uniform 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 these
information 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.)

In a dynamic model, data flow diagrams and process diagrams
are used to determine the flow of information.
An XML document consists of:
Processing Instruction (PI)
Tags
Elements
Content
Attributes
Entities
Comments


Xml session01

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