DTD - Entity
An entity is a variable used to define shortcuts that reference plain text or special characters.
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Entity references are references to entities.
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Entities can be declared internally or externally.
An internal entity declaration
Syntax
<!ENTITY entity-name "entity-value">
Example
DTD example:
<!ENTITY writer "Donald Duck.">
<!ENTITY copyright "Copyright example.com">
XML example:
<author>&writer;©right;</author>
<!ENTITY writer "Donald Duck.">
<!ENTITY copyright "Copyright example.com">
XML example:
<author>&writer;©right;</author>
Note:An entity consists of three parts: an ampersand (&), an entity name, and a semicolon (;).
An external entity declaration
Syntax
<!ENTITY entity-name SYSTEM "URI/URL">
Example
DTD example:
<!ENTITY writer SYSTEM "http://www.example.com/entities.dtd">
<!ENTITY copyright SYSTEM "http://www.example.com/entities.dtd">
XML example:
<author>&writer;©right;</author>
<!ENTITY writer SYSTEM "http://www.example.com/entities.dtd">
<!ENTITY copyright SYSTEM "http://www.example.com/entities.dtd">
XML example:
<author>&writer;©right;</author>