Description of Attribute Properties in DTDs

Type

Attribute

All attribute nodes have this type.

Name

String

Identifier for the particular attribute.

Restrictions

Fixed

The attribute is required and it must always have the value specified by the Default property. You must always explicitly specify this attribute.

 

Implied

The attribute is optional. There is no default value.

 

Optional

The attribute is optional. If you do not specify it, the XML parser uses the value of the Default property.

 

Required

The element must always explicitly specify this attribute and assign a value to it.

Content Type

CDATA

The attribute value can contain any valid character data. It is a text string.

 

Entity

The attribute value is the name of an entity defined in the DTD.

 

Entities

The attribute value is a space-separated list of entities that are defined in the DTD.

 

Enumerated

The attribute value is one of a set of specified values. When the value of the Content Type property is Enumerated, the attribute has an additional property: Allowed Values. Specify the allowed values in a space-separated list.

 

ID

The attribute value is a unique name within the DTD.

 

IDREF

The attribute value is an ID that is defined in the DTD.

 

IDREFs

The attribute value is a space-separated list of IDs that are defined in the DTD.

 

NMToken

The attribute value is a valid XML name that is composed of letters, numbers, hyphens, underscores, and colons.

 

NMTokens

The attribute value is a space-separated list of name tokens.

 

Notation

The name of a notation specified in the DTD. The notation describes a non-XML data format, such as those used for image files. When the value of the Content Type property is Notation, the attribute has an additional property: Allowed Values. Specify the allowed values in a space-separated list.