AttributeType Element

Defines an attribute type for use within the Schema element.

<AttributeType
    default="default-value" 
    dt:type="primitive-type" 
    dt:values="enumerated-values" 
    name="idref" 
    required="{yes | no}">

Attributes

default: Default value for the attribute. The default value must be legal for that attribute instance. For example, when the attribute is an enumerated type, the default value must appear in the values list.
dt:type: Specifies the data type for this attribute type. In the implementation provided with Internet Explorer 5, an attribute can take one of the following types: entity, entities, enumeration, id, idref, idrefs, nmtoken, nmtokens, notation, or string. When the type "enumeration" is selected, the dt:values attribute should also be supplied, listing the allowed values. For more information about data types, see XML Data Types.
dt:values: When dt:type is set to "enumeration," this attribute lists the possible values.
name: Name of the attribute type. This attribute is required. References to this attribute type within an ElementType definition are made in the schema with the attribute element. The name supplied here corresponds to the type attribute of the attribute element.
required: Indicator of whether the attribute must be present on the element.

Element Information

Number of occurrences	Unlimited
Parent elements	ElementType, Schema
Child elements	datatype, description
Requires closing tag	Yes. XML Schema is an XML grammar and like all XML grammars, all tags must have closing tags to satisfy the definition of well-formed.

Remarks

An AttributeType declaration contained within an ElementType element defines that attribute type within the scope of the ElementType that contains it.

In XML Schema, as in XML 1.0, the order of appearance of attributes in an element is not constrained and a given attribute can appear no more than once in an element.

Example

The following example shows an enumeration and its DTD equivalent:

<AttributeType name="colors" dt:type="enumeration"
  dt:values="red green blue">
<!ATTLIST x colors (red | green | blue)>

The following example declares an attribute type called "myattr." This declaration constrains "myattr" attributes to contain only a name token.

<AttributeType name="myattr" dt:type="nmtoken"/>