Xml
Download as PPT, PDF0 likes609 views
The document provides an overview of XML basics including: - XML stands for Extensible Markup Language and is used to carry data, not display it. Users define their own tags. - XML documents must have an XML declaration specifying the version and encoding. They must also have a root element containing other properly nested elements. - Namespaces are used to avoid conflicts when mixing XML from different sources by prefixing elements. - CDATA and PCDATA sections define how character data is handled within XML elements. - Documents are considered well-formed if they follow XML syntax rules and valid if they also conform to DTD rules.
![CDATA - (Unparsed) Character Data The term CDATA is used about text data that should not be parsed by the XML parser. Characters like "<" and "&" are illegal in XML elements. "<" will generate an error because the parser interprets it as the start of a new element. "&" will generate an error because the parser interprets it as the start of an character entity. Some text, like JavaScript code, contains a lot of "<" or "&" characters. To avoid errors script code can be defined as CDATA. Everything inside a CDATA section is ignored by the parser. A CDATA section starts with " <![CDATA[ " and ends with " ]]> ": A CDATA section cannot contain the string "]]>". Nested CDATA sections are not allowed. The "]]>" that marks the end of the CDATA section cannot contain spaces or line breaks.](https://image.slidesharecdn.com/xml-124250084363-phpapp01/85/Xml-17-320.jpg)
![Example <script> <![CDATA[ function matchwo(a,b) { if (a < b && a < 0) then { return 1; } else { return 0; } } ]]> </script>](https://image.slidesharecdn.com/xml-124250084363-phpapp01/85/Xml-18-320.jpg)
Xml
- 1. XML Basics Training Arshi Arora
- 2. Agenda What is XML XML Naming Rules Displaying XML Files with CSS XML Namespaces Character Data-CDATA Parsed Character Data-PCDATA Well Formed XML Documents
- 3. What is XML? XML stands for E X tensible M arkup L anguage . XML is a markup language much like HTML XML was designed to carry data , not to display data XML tags are not predefined. You must define your own tags XML is designed to be self-descriptive
- 4. An Example <?xml version="1.0" encoding="ISO-8859-1"?> <note> <to>Tove</to> <from>Jani</from> <heading>Reminder</heading> <body>Don't forget me this weekend!</body> </note>
- 5. XML Declaration The XML declaration in the document map consists of the following: The version number, <?xml version="1.0"?> . This is mandatory. Although the number will change for future versions of XML, 1.0 is the current version. The encoding declaration, <?xml version="1.0" encoding="UTF-8"? > This is optional. If used, the encoding declaration must appear immediately after the version I information in the XML declaration, and must contain a value representing an existing character encoding.
- 6. An XML declaration may also contain a standalone declaration, for example, <?xml version="1.0" encoding="UTF-8" standalone="yes"?> Like the encoding declaration, the standalone declaration is optional. If used, the standalone declaration must appear last in the XML declaration.
- 7. Encoding Declaration The encoding declaration identifies which encoding is used to represent the characters in the document. Although XML parsers can determine automatically if a document uses the UTF-8 or UTF-16 Unicode encoding, this declaration should be used in documents that support other encodings. For example, the following is the encoding declaration for a document that uses the ISO-8859-1 (Latin 1). <?xml version="1.0" encoding =" ISO-8859-1 "?> Case in the value specified is not considered by the encoding declaration. "ISO-8859-1" is the equivalent of "iso-8859-1" . The following is the encoding declaration for a document that uses the Japanese encoding method Shift-JIS. <?xml version="1.0" encoding="Shift-JIS"?>
- 8. Standalone Declaration The standalone declaration indicates whether a document relies on information from an external source, such as external document type definition (DTD), for its content. If the standalone declaration has a value of "yes" , for example, <?xml version="1.0" standalone="yes"?> , the parser will report an error if the document references an external DTD or external entities.
- 9. XML Naming Rules XML elements must follow these naming rules: Names can contain letters, numbers, and other characters Names must not start with a number or punctuation character Names must not start with the letters xml (or XML, or Xml, etc) Names cannot contain spaces
- 10. Some important points XML Document forms a tree structure All XML Elements must have a closing Tag XML Tags are case sensitive XML Elements must be properly nested XML Documents Must Have a Root Element XML Attribute Values Must be Quoted
- 11. Attributes in xml <gangster name='George "Shotgun" Ziegler'> <gangster name="George "Shotgun" Ziegler">
- 12. Displaying XML Files with CSS XML File <?xml version="1.0" encoding="ISO-8859-1"?> <?xml-stylesheet type="text/css" href="cd_catalog.css"?> <CATALOG> <CD> <TITLE>Empire Burlesque</TITLE> <ARTIST>Bob Dylan</ARTIST> <YEAR>1985</YEAR> </CD> <CD> <TITLE>Hide your heart</TITLE> <ARTIST>Bonnie Tyler</ARTIST> <YEAR>1988</YEAR> </CD> </CATALOG>
- 13. CSS file CATALOG { background-color: #ffffff; width: 100%; } CD {display: block; margin-bottom: 30pt; margin-left: 0; } TITLE {color: #FF0000; font-size: 20pt; } ARTIST {color: #0000FF; font-size: 20pt; } YEAR { display: block; color: #000000; margin-left: 20pt; }
- 14. Name Conflicts In XML, element names are defined by the developer. This often results in a conflict when trying to mix XML documents from different XML applications. Solving the Name Conflict Using a Prefix Name conflicts in XML can easily be avoided using a name prefix. <h:table> <h:tr> <h:td>Apples</h:td> <h:td>Bananas</h:td> </h:tr> </h:table> <f:table> <f:name>African Coffee Table</f:name> <f:width>80</f:width> <f:length>120</f:length> </f:table>
- 15. XML Namespaces - The xmlns Attribute When using prefixes in XML, a so-called namespace for the prefix must be defined. The namespace is defined by the xmlns attribute in the start tag of an element. The namespace declaration has the following syntax. xmlns: prefix =" URI ".
- 16. Namespace Example <root> <h:table xmlns:h="http://www.w3.org/TR/html4/"> <h:tr> <h:td>Apples</h:td> <h:td>Bananas</h:td> </h:tr> </h:table> <f:table xmlns:f="http://www.w3schools.com/furniture"> <f:name>African Coffee Table</f:name> <f:width>80</f:width> <f:length>120</f:length> </f:table> </root>
- 17. CDATA - (Unparsed) Character Data The term CDATA is used about text data that should not be parsed by the XML parser. Characters like "<" and "&" are illegal in XML elements. "<" will generate an error because the parser interprets it as the start of a new element. "&" will generate an error because the parser interprets it as the start of an character entity. Some text, like JavaScript code, contains a lot of "<" or "&" characters. To avoid errors script code can be defined as CDATA. Everything inside a CDATA section is ignored by the parser. A CDATA section starts with " <![CDATA[ " and ends with " ]]> ": A CDATA section cannot contain the string "]]>". Nested CDATA sections are not allowed. The "]]>" that marks the end of the CDATA section cannot contain spaces or line breaks.
- 18. Example <script> <![CDATA[ function matchwo(a,b) { if (a < b && a < 0) then { return 1; } else { return 0; } } ]]> </script>
- 19. PCDATA - Parsed Character Data XML parsers normally parse all the text in an XML document. When an XML element is parsed, the text between the XML tags is also parsed. The parser does this because XML elements can contain other elements
- 20. Well Formed XML Documents A "Well Formed" XML document has correct XML syntax. The syntax rules were described in the previous chapters : XML documents must have a root element XML elements must have a closing tag XML tags are case sensitive XML elements must be properly nested XML attribute values must be quoted
- 21. Valid XML Documents A "Valid" XML document is a "Well Formed" XML document, which also conforms to the rules of a Document Type Definition (DTD)
- 22. Thanks