What is XML?
Answer
XML, Extensible Markup Language, is an open, text based markup
language that provides structural and semantic information to data. XML is a
metalanguage that can be used to create other language. It is used to structure
and describe data that can be understood by other applications. Using XML, we
can separate the user interface from data.
Features of XML
XML is a generalized markup language that means one can define his/her
own tag sets.
A valid XML document contains rules and is self-describing.
The rules that are found in DTD allow the documents to be validated.
Describe the logical structure of XML.
Answer
XML documents comprise of declaration, elements and comments
XML Declaration
It identifies the version to which XML conforms
<?xml version = "1.0"?>
Document Type Declaration
It consists of markup code that indicates grammar rules or Document
Type Definition (DTD) for the particular class of document.
<! DOCTYPE Car SYSTEM "cr.dtd">
This statement tells the XML processor that the document is of the class Car
that conforms the rules specified in the DTD "cr.dtd".
Document element
The document element contains data of an XML document.
Why is XML so popular?
Answer
Due to the following advantages of using XML, it has become popular:
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It supports Unicode. Therefore documents written in any human language can be
communicated.
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Data structures: records, lists and trees can be represented using XML.
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Its format describes structure, field names and their specific values too. Its
therefore called self-documenting.
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Its syntax and parsing requirements make the necessary parsing algorithms very
simple, efficient, and consistent.
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It can be used as a document storage and processing format.
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It is platform-independent.
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Why is XML referred as self-describing data?
Answer
Text labels inside of XML's syntactic delimiters that cause most
people to think that XML is self-describing. But these tags aren't part of XML.
Choosing the terms used for tags or naming anything is often a difficult and
contentious activity. Everyone naturally creates names that make sense to them.
However, XML is not self describing.
Why is XML extensible?
Answer
Extensibility is another attribute of XML. XML is short of "eXtensible
Markup Language. This is so because a developer may easily create his own XML
syntax for any applications he wishes to use it for. Any other developer, once
having learned how to use his own language's XML parsing routines, can use any
XML-based format currently available.
XML is a secured language for information exchange over the network. Explain
Answer
Applications require a secure exchange of structured data. XML
encryption can ensure this by providing end-to-end security as it is iitself a
widely used data structuring technology.
XML encryption addresses the issues not covered in by the TLS which are
encrypting part of the data that is being exchanged and secure sessions between
multiple parties.
XML Encryption can handle XML as well as binary data.
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More XML Links
Answer - They must have a root tag, the document should be well
formed : the tags should be properly closed, since XML is case sensitive, one
should take care..............
Answer - XML DTD is a rule book that an XML document follows.
Once DTD is ready, you can create number of XML documents following the same
rules..............
Answer - The term CDATA is used when you dont want some text
data to be parsed by the XML parser. ..............
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