PRB: MSXML 4.0: Error Message When You Load an XSD Schema in an XMLSchemaCache Object (316635)
The information in this article applies to:
This article was previously published under Q316635 SYMPTOMS
When you load an XML Schema definition language (XSD) schema into an MSXML 4.0 XMLSchemaCache object, you may receive the following error message:
<all> is not the only particle in a <group> or is being used as an extension.
CAUSE
This may occur if the schema contains a complex type that derives from another complex type whose content model is defined by using an <xsd:all> grouping particle, as follows:
<?xml version="1.0"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<xsd:complexType name="address">
<xsd:all>
<xsd:element name="name" type="xsd:string"/>
<xsd:element name="street" type="xsd:string"/>
<xsd:element name="city" type="xsd:string"/>
</xsd:all>
</xsd:complexType>
<xsd:complexType name="USAddress">
<xsd:complexContent>
<xsd:extension base="address">
<xsd:all>
<xsd:element name="state" type="USState"/>
<xsd:element name="zipcode" type="xsd:positiveInteger"/>
</xsd:all>
</xsd:extension>
</xsd:complexContent>
</xsd:complexType>
</xsd:schema>
RESOLUTION
To work around this problem, use either of the following methods:
- Use the <sequence> element rather than the <all> element to define the content model of the parent type.
- Use the <sequence> element to define a new complex type instead of extending a type that uses the <all> element.
For example, you can use the following schema:
<?xml version="1.0"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<xsd:complexType name="address">
<xsd:all>
<xsd:element name="name" type="xsd:string"/>
<xsd:element name="street" type="xsd:string"/>
<xsd:element name="city" type="xsd:string"/>
</xsd:all>
</xsd:complexType>
<xsd:complexType name="USAddress">
<xsd:all>
<xsd:element name="name" type="xsd:string"/>
<xsd:element name="street" type="xsd:string"/>
<xsd:element name="city" type="xsd:string"/>
<xsd:element name="state" type="xsd:string"/>
<xsd:element name="zipcode" type="xsd:positiveInteger"/>
</xsd:all>
</xsd:complexType>
</xsd:schema>
STATUSThis behavior is by design.MORE INFORMATION
According to the World Wide Web Consortium (W3C) specifications, <all> model groups may appear only at the top level of a complexType or group element, and must be the only particle in the group.
When an extension type is built in XSD, it is regarded as a sequence that contains the base type and the extension. For example, the derived USAddress complexType element from the schema that is described in the "Cause" section resembles the following:
<xsd:complexType name="USAddress">
<xsd:sequence>
<xsd:all>
<xsd:element name="name" type="xsd:string"/>
<xsd:element name="street" type="xsd:string"/>
<xsd:element name="city" type="xsd:string"/>
</xsd:all>
<xsd:all>
<xsd:element name="state" type="USState"/>
<xsd:element name="zipcode" type="xsd:positiveInteger"/>
</xsd:all>
</xsd:sequence>
</xsd:complexType>
This violates the rule that <all> model groups must appear at the top level of a complexType or group element, and must be the only particle in the group.
Steps to Reproduce Behavior
Save the sample schema that is described in the "Cause" section in a file named Address-schema.xsd, and then add the schema to an MSXML 4.0 XMLSchemaCache object, as in the following Microsoft Visual Basic sample:
Dim xmlschema As MSXML2.XMLSchemaCache40
Set xmlschema = New MSXML2.XMLSchemaCache40
xmlschema.Add "", app.path & "\address-schema.xsd"
When the Add method is called, the XSD is checked to ensure that it conforms to the W3C XSD specifications. Because this schema does not conform to the specifications, you receive an error message.
REFERENCES
For more information on W3C specifications, see the following Web sites:
| Modification Type: | Major | Last Reviewed: | 3/18/2002 |
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| Keywords: | kbDSupport kbprb KB316635 |
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