XML

History Markup Languages

What is a Markup language? A set of labels that are embedded within text to distinguish individual elements or groups of elements for display or identification purposes. The labels are typically known as “tags”. A markup language combines text and extra information about the text. The best-known markup language in modern use is HTML (HyperText …

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Introduction to XML

Introduction to XML   The eXtensible Markup Language (XML) is a general-purpose markup language. Its primary purpose is to facilitate the sharing of data across different information systems, particularly via the Internet. So, please get your fact right about XML, XML is meant for data exchange not for data storage. XML is a simplified subset …

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XML and SGML

1. Differences between XML and SGML XML allows only documents that use the SGML declaration in this note. This declares all the following SGML features as: • DATATAG • OMITTAG • RANK • LINK (SIMPLE, IMPLICIT and EXPLICIT) • CONCUR • SUBDOC • FORMAL Note that it differs from the reference concrete syntax in a …

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HTML In XML

XML is conceived of as a way to extend the power of online delivery of information. Although both XMLand HTML are derived from SGML (Standard Generalized Markup Language), there are important differences between the two markup languages. For one, HTML provides a fixed set of tags, while XMLenables users to define the tags that they …

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Why XML ?

In order to appreciate XML, it is important to understand why it was created. XML was created so that richly structured documents could be used over the web. The only viable alternatives, HTML and SGML, are not practical for this purpose. HTML has been developed for something else and is not suited for data exchange …

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XML Syntax and Elements

XML Syntax and Elements   XML is used for structured, descriptive markup. Each XML element can contain text, other XMLelements that are known as its children, or nothing. In designing an XML document, we should think about what will contain what. You can think of the structure as a family tree with many branches, or …

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Attributes In XML

Unlike in HTML, XML requires that all XML attributes have a value. This means all attributes have to be equal to something! Below is the correct way to create an attribute in XML.   If elements are nouns defining what something is, attributes are adjectives modifying the nouns. In general, data itself should be stored …

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XML Entity References

An entity references in xml is a symbolic representation of information. What does that mean? Well, let’s imagine for a moment that we wanted to create an introduction that is included in every single letter that we write. It would be monotonous to have to type out a three sentence introduction for every letter, but …

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XML Comments

XML comments have the exact same syntax as HTML comments. A comment is used to temporarily edit out a portion of XML code or to leave a note . Although XML is a supposed to be self-describing data, you may still come across some instances where an XML comment might be necessary. Below is an …

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XML Syntax and Elements

XML syntax   XML is used for structured, descriptive markup. Each XML element can contain text, other XMLelements that are known as its children, or nothing. In designing an XML document, we should think about what will contain what. You can think of the structure as a family tree with many branches, or as containers …

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XML Attributes

Unlike in HTML, XML requires that all XML attributes have a value. This means all attributes have to be equal to something! Below is the correct way to create an attribute in XML.   If elements are nouns defining what something is, attributes are adjectives modifying the nouns. In general, data itself should be stored …

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XML Entity References

An entity is a symbolic representation of information. What does that mean? Well, let’s imagine for a moment that we wanted to create an introduction that is included in every single letter that we write. It would be monotonous to have to type out a three sentence introduction for every letter, but not to worry, …

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Comments In XML

XML comments have the exact same syntax as HTML comments. A comment is used to temporarily edit out a portion of XML code or to leave a note . Although XML is a supposed to be self-describing data, you may still come across some instances where an XML comment might be necessary. Below is an …

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What is a Document?

An XML document is a set of user defined elements(tags), that are used to define and describe structure of a document. Using these elements we can define “who contain what”. XML Document   Remember, unlike HTML, XML does not have any predefined tags (elements) to use! Yes that’s true there is no predefined tags in …

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Well- Formed XML Document

A “Well Formed” XML document has correct XML syntax and follows XML rules for naming elements, attributes etc.   A “Well Formed” XML document is a document that conforms to the XML syntax rules, i.e.:   • XML tags are case sensitive • XML documents must have a root element, only one root element is …

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Valid XML Document

An XML document that complies with a particular schema, in addition to being well-formed, is said to be valid. A “Valid” XML document also conforms to a DTD.   A “Valid” XML document is a “Well Formed” XML document, in addition it also conforms to the rules of a Document Type Definition (DTD):   <?xml …

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Introduction to DTD In XML

Document Type Definition (DTD), defined to some extent differently within the XML and SGMLspecifications, is one of several SGML and XML schema languages, and is the term used to describe a document or portion thereof that is authored in the DTD language. A DTD is primarily used for the expression of a schema via a …

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DTD Elements In XML

The purpose of a DTD is to define the legal building blocks of an XML document. It defines the document structure with a list of legal elements. A DTD can be declared inline in your XML document, or as an external reference. XML provides an application independent way of sharing data. With a DTD, independent …

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DTD Attributes IN XML

In the DTD, XML element attributes are defined with an ATTLIST declaration.   An attribute declaration has the following syntax:   <!ATTLIST element-name attribute-name attribute-type default-value>   Tthe ATTLIST declaration defines the element which can have the attribute, attribute-name is the name of the attribute, attribute-type is the type of the attribute, and the default …

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