XML interview questions

<-Pre

Home

Next->

Best XML interview questions.

What is XML?
XML is the Extensible Markup Language. It improves the functionality of the Web by letting you identify your information in a more accurate, flexible, and adaptable
way.

It is extensible because it is not a fixed format like HTML (which is a single, predefined markup language).Instead, XML is actually a metalanguage—a language for
describing other languages—which lets you design your own markup languages for limitless different types of documents.

XML is not a single predefined markup language : it’s a metalanguage - a language for describing other languages.

XML is sometimes referred to as ‘self-describing data’ because the names of the markup elements should represent the type of content they hold.

What is a markup language?
A markup language is a set of words and symbols for describing the identity of pieces of a document (for example ‘this is a heading’,‘this is a list’, ‘this is the caption of this figure’,etc). Programs can use this with a style sheet to create
output for screen, print, audio, video, Braille, etc.

^Back to top

Where should I use XML?
Its goal is to enable generic SGML to be served,received, and processed on the Web in the way that is now possible with HTML. XML has been designed for ease of implementation and for interoperability with both SGML and HTML.

Despite early attempts, browsers never allowed otherSGML, only HTML (although there were plugins), and they allowed it (even encouraged it) to be corrupted or
broken, which held development back for over a decade by making it impossible to program for it reliably. XML fixes that by making it compulsory to stick to the
rules, and by making the rules much simpler than SGML.


But XML is not just for Web pages: in fact it's very rarely used for Web pages on its own because browsers still don't provide reliable support for formatting and
transforming it. Common uses for XML include:

>you can define your own markup, you can define meaningful names for all your information items.

>XML is portable and non-proprietary, it can be used to store textual information across any platform. Because it is backed by an international standard, it will remain accessible and processable as a data format.

>XML can therefore be used to store and identify any kind of (hierarchical information structure, especially for long, deep, or complex document sets or data sources, making it ideal for an information-management back-end
to serving the Web. This is its most common Web application, with a transformation system to serve it as HTML until such time as browsers are able to handle XML
consistently. Publishing

What is SGML?
SGML (Standard Generalized Markup Language) is a language for defining markup languages such as HTML and for specifying the rules for tagging elements in a document. SGML itself is not a markup language; rather, it is a language to create markup languages. SGML supports the definition of markup languages that are hardware-and software-independent. SGML was developed and standardized by the International Organization for Standardization (ISO), which published it in 1986. Because of SGML's complexity, HTML and XML were developed as simplified subsets of SGML for use on the Internet.

^Back to top

aren't XML, SGML, and HTML all the same thing?
SGML is the mother tongue, and has been used for describing thousands of different document types in many fields of human activity,from transcriptions of ancient Irish manuscripts to the technical documentation for stealth bombers, and from patients’ clinical records to musical notation.
SGML is very large and complex, however, and probably overkill for most common office desktop applications.
Wheras, XML is an abbreviated version of SGML, to make it easier to use over the Web, easier for you to define your own document types, and easier for programmers to write programs to handle them.
It omits all the complex and less-used options of SGML in return for the benefits of being easier to write applications for, easier to understand, and more suited to delivery and interoperability over the Web. But it is still SGML, and XML files may still be processed in the same way as any other SGML file.
And,HTML is just one of many SGML or XML applications—the one most frequently used on the Web. Technical readers may find it more useful to think of XML as being SGML– rather than HTML++.

Pre->Javascript

Next->XML