Internal and External DTD Declaration
You can declare DTD internally or as an
external file
Internal Declaration
External Declaration
Internal Declaration
<?xml
version="1.0"?>
<!DOCTYPE note [
<!ELEMENT note
(to,from,heading,body)>
<!ELEMENT to (#PCDATA)>
<!ELEMENT from
(#PCDATA)>
<!ELEMENT heading
(#PCDATA)>
<!ELEMENT body
(#PCDATA)>
]>
<note>
<to>Raju</to>
<from>Ravi</from>
<heading>Reminder</heading>
<body>Don't forget me
this weekend</body>
</note>
!DOCTYPE note defines that the
root element of this document is note.
!ELEMENT note defines that the
note element contains four elements: "to,from,heading,body". !ELEMENT
to defines the to element to be of the type "#PCDATA".
!ELEMENT from defines the from
element to be of the type "#PCDATA".
!ELEMENT heading defines the
heading element to be of the type "#PCDATA".
!ELEMENT body defines the body
element to be of the type "#PCDATA".
External Declaraton
If
the DTD is declared in an external file, it should be wrapped in a DOCTYPE
definition with the following syntax:
<!DOCTYPE
root-element SYSTEM "filename">
<?xml
version="1.0"?>
<!DOCTYPE
note SYSTEM "note.dtd">
<note>
<to>Raju</to>
<from>Ravi</from>
<heading>Reminder</heading>
<body>Don't forget me
this weekend!</body>
</note>
And
this is the file "note.dtd" which contains the DTD:
<!ELEMENT
note (to, from, heading, body)>
<!ELEMENT
to (#PCDATA)>
<!ELEMENT
from (#PCDATA)>
<!ELEMENT
heading (#PCDATA)>
<!ELEMENT
body (#PCDATA)>
Internal And External Entities in DTD
Internal Entities
|
External Entities
|
Internal defined as Entities that located local system
|
It can defined as an entity which is located in remote
system
|
Syntax:
<! ENTITY entity_ name Entity _value>
|
Syntax:
<! ENTITY entity_name SYSTEM "Entity_path">
|
DTD Example:
<!ENTITY author "Uttam K Roy">
<IENTITY copyrights "OxfordUniversity">
|
DTD Example:
<!ENTITY author SYSTEM http ://loca I host: 8080/exa
mpple/Exa mple.dtd >
<!ENTITY copyrights SYSTEM
http://localhost:8080/exampple/Example.dtd>
|
XML Example:
<editor>&author; &
copyrights;</editor>
|
XML Example:
<editor>&author; &
copyrights;</editor>
|
