Xml
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XML DTD defines the structure and elements of an XML document. An XML schema also defines the structure of an XML document and specifies elements, attributes, data types. The example XML document uses a DTD to validate that the elements <to>, <from>, <heading>, and <body> are in the correct order within the <note> tags.
![DTD
<?xml version="1.0"?>
<!DOCTYPE note [
<!ELEMENT note (to,from,heading,body)>
<!ELEMENT to (#PCDATA)>
<!ELEMENT from (#PCDATA)>
<!ELEMENT heading (#PCDATA)>
<!ELEMENT body (#PCDATA)>
<!ENTITY writer "Donald Duck.">
<!ENTITY copyright "Copyright “>
]>
<note>
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend ></body>
</note>](https://image.slidesharecdn.com/xml-200223021149/85/Xml-3-320.jpg)
Xml
- 1. XML
- 2. XML • A DTD is a Document Type Definition. • A DTD defines the structure and the legal elements and attributes of an XML document. • With a DTD, independent groups of people can agree on a standard DTD for interchanging data. • An application can use a DTD to verify that XML data is valid.
- 3. DTD <?xml version="1.0"?> <!DOCTYPE note [ <!ELEMENT note (to,from,heading,body)> <!ELEMENT to (#PCDATA)> <!ELEMENT from (#PCDATA)> <!ELEMENT heading (#PCDATA)> <!ELEMENT body (#PCDATA)> <!ENTITY writer "Donald Duck."> <!ENTITY copyright "Copyright “> ]> <note> <to>Tove</to> <from>Jani</from> <heading>Reminder</heading> <body>Don't forget me this weekend ></body> </note>
- 4. XML Schema An XML Schema describes the structure of an XML document. The XML Schema language is also referred to as XML Schema Definition (XSD). The purpose of an XML Schema is to define the legal building blocks of an XML document: • the elements and attributes that can appear in a document • the number of (and order of) child elements • data types for elements and attributes • default and fixed values for elements and attributes
- 5. XSD SYNTAX <?xml version="1.0"?> <xs:schema > <xs:element name="note"> <xs:complexType> <xs:sequence> <xs:element name="to" type="xs:string"/> <xs:element name="from" type="xs:string"/> <xs:element name="heading" type="xs:string"/> <xs:element name="body" type="xs:string"/> </xs:sequence> </xs:complexType> </xs:element> </xs:schema>
- 6. Xml schema <?xml version="1.0"?> <!DOCTYPE note SYSTEM "https://www.w3schools.com/xml/note.dtd"> <note> <to>Tove</to> <from>Jani</from> <heading>Reminder</heading> <body>Don't forget me this weekend!</body> </note>