DTD - 实体

Entities are variables used to define shortcuts to common text.
实体是用于定义普通文本快捷方式的变量。

- Entity references are references to entities.
实体参数就是反映实体特征的参数。
- Entities can be declared internal, or external
实体可以声明为内部实体或外部实体。

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Internal Entity Declaration
内部实体声明

Syntax: <!ENTITY entity-name "entity-value"> DTD Example: <!ENTITY writer "Donald Duck."> <!ENTITY copyright "Copyright W3Schools."> XML example: <author>&writer;&copyright;</author>

 

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External Entity Declaration
外部实体声明

Syntax: <!ENTITY entity-name SYSTEM "URI/URL"> DTD Example: <!ENTITY writer SYSTEM "http://www.w3schools.com/dtd/entities.dtd"> <!ENTITY copyright SYSTEM "http://www.w3schools.com/dtd/entities.dtd"> XML example: <author>&writer;&copyright;</author>