ElementType Element

Defines an element type for use within the Schema element.

<ElementType
  content="{empty | textOnly | eltOnly | mixed}" 
  dt:type="datatype" 
  model="{open | closed}" 
  name="idref" 
  order="{one | seq | many}">

Attributes

content

Indicator of whether the content must be empty or can contain text, elements, or both. The following values can be assigned to this attribute. The default value for the content attribute is "mixed." Note that when the content attribute is set to "mixed", the order attribute requires a "many" value.

empty	The element cannot contain content.
textOnly	The element can contain only text, not elements. Note that if the model attribute is set to "open," the element can contain text and other unnamed elements.
eltOnly	The element can contain only the specified elements. It cannot contain any free text.
mixed	The element can contain a mix of named elements and text. Mixed is the default value. Note that if the value of the content attribute is mixed, minOccurs and maxOccurs attributes will not trigger a validation error if the number of child elements is outside the specified boundary.

Example

<ElementType name="x" content="empty"/>
<ElementType name="x" content="textOnly"/>
<ElementType name="x" content="eltOnly">
  <element type="y"/>
</ElementType>
<ElementType name="x" content="mixed">
  <element type="q"/>
  <element type="r"/>
</ElementType>

The DTD equivalent is as follows:

empty: <!ELEMENT x EMPTY>
textOnly: <!ELEMENT x (#PCDATA)>
eltOnly: <!ELEMENT x y>
mixed: <!ELEMENT x (#PCDATA | q | r)*>

dt:type

Data type of the element. The valid data types are defined in the XML Data Types Preview.

model

Indicator of whether the content can include only what is defined in the content model or can contain content not specified in the model. Default is "open."

<ElementType name="x" model="open"/>

When the model is defined as open, the element can include additional elements or attributes not declared explicitly in the content model. These additional tags can come from the same namespace or a different namespace. If they are in the same namespace, there must be a corresponding ElementType or AttributeType definition for them in the schema.

When the model is defined as closed, the element cannot include elements and cannot include mixed content not specified in the content model. The DTD uses a closed model.

name

Name of the element. This attribute is required. If this element type is declared as a valid child of another element type, this name is specified within an element element.

<ElementType name="x">
</ElementType> 

The DTD equivalent is as follows:

<!ELEMENT x EMPTY> 

order

The following values can be assigned to this attribute.

one	Permits only one of a set of elements. Note that for a document to correctly validate when the one attribute is specified, the model attribute for the ElementType must be specified as "closed."
seq	Requires the elements to appear in the specified sequence.
many	Permits the elements to appear (or not appear) in any order. If you specify "many" for the order attribute, maxOccurs values are no longer relevant during validation.

The "seq" setting is needed to specify valid sequences. For example, it can be used to specify when a particular sequence is valid—such as "x1,y1" or "x2,y2"—but no other possible combinations are valid. The "seq" value serves the same role as parentheses in a DTD. The default value is "many."

The following example demonstrates the "one" setting. Note that the value of the model attribute must be "closed" when "one" is specified for the order attribute.

<ElementType name="z" content="eltOnly" order="one" model="closed">
<element type="x" minOccurs="1" maxOccurs="1"/>
<element type="y" minOccurs="1" maxOccurs="1"/>
</ElementType>

The following example demonstrates the "seq" setting:

<ElementType name="x" content="eltOnly" order="one" model="closed">
  <group order="seq" content="eltOnly" model="closed">
    <element type="x1"/>
    <element type="y1"/>
  </group>
  <group order="seq" content="eltOnly" model="closed">
    <element type="x2"/>
    <element type="y2"/>
  </group>
</ElementType>

The following example demonstrates the "many" setting:

<ElementType name="x" content="eltOnly" order="many" model="closed">
  <element type="q"/>
  <element type="r"/>
</ElementType>

It's important to note that the "many" setting of the order attribute makes the minOccurs and maxOccurs attributes irrelevant during validation. Rather than using the "many" setting for the order attribute in conjunction with minOccurs and maxOccurs, use the "seq" setting instead. For example, consider the following schema. Notice at the bottom of the sample that order="seq" is set.

<?xml version="1.0"?>
<Schema name="SampleSchema" xmlns="urn:schemas-microsoft-com:xml-data"
    xmlns:dt="urn:schemas-microsoft-com:datatypes">
    <ElementType name="PublisherID" model="closed" dt:type="ID"
      content="textOnly">
    </ElementType>
    <ElementType name="PublisherName" model="closed" dt:type="string"
      content="textOnly">
    </ElementType>

    <ElementType name="Publisher" model="closed" content="eltOnly"
      order="many">
      <element type="PublisherID"/>
      <element type="PublisherName"/>
    </ElementType>

    <ElementType name="Book" model="closed" content="eltOnly"
      order="seq">
    <element type="Publisher" minOccurs="1" maxOccurs="1"/>
    </ElementType>  

</Schema> 

Now if the following XML document is validated against the above schema, the validation fails because the number of <Publisher> elements exceeds the specified maxOccurs value of "1". However, if the order value is set to "many," the validation would incorrectly succeed because the maxOccurs="1" setting would be ignored.

<?xml version='1.0'?>
<Book xmlns="x-schema:orderschema.xml" >

<Publisher>
    <PublisherID>P1</PublisherID>
    <PublisherName>GG&G</PublisherName>
</Publisher>
<Publisher>
    <PublisherID>P2</PublisherID>
    <PublisherName>North</PublisherName>
</Publisher>

</Book>

Element Information

Remarks

The term "element type" refers to the element type of which all elements sharing a name are instances. Element types are declared in schemas; elements occur in documents. Element types are declared with the ElementType element type.

Example

<ElementType name="x">
  <!-- element content declarations go here -->
</ElementType>