Executing XPath Queries (SQLXMLOLEDB Provider)

This example illustrates the use of the following SQLXMLOLEDB Provider-specific properties:

• ClientSideXML
• Base Path
• Mapping Schema

In this sample ADO application, an XPath query (root) is specified against an XSD mapping schema (MySchema.xml). The schema has a <Contacts> element with ContactID, FirstName, and LastName attributes. In the schema, default mapping takes place: an element name maps to the table with the same name, and attributes of simple type map to the columns with the same names.

<xsd:schema xmlns:xsd='http://www.w3.org/2001/XMLSchema'
   xmlns:sql='urn:schemas-microsoft-com:mapping-schema'>
 <xsd:element name= 'root' sql:is-constant='1'> 
    <xsd:complexType>
       <xsd:sequence>
         <xsd:element ref = 'Contacts'/>
       </xsd:sequence>
    </xsd:complexType>
  </xsd:element>
  <xsd:element name='Contacts' sql:relation='Person.Contact'> 
     <xsd:complexType>
          <xsd:attribute name='ContactID' type='xsd:integer' />
          <xsd:attribute name='FirstName' type='xsd:string'/> 
          <xsd:attribute name='LastName' type='xsd:string' /> 
     </xsd:complexType>
   </xsd:element>
</xsd:schema>

The Mapping Schema property provides the mapping schema against which the XPath query is executed. The mapping schema can be an XSD or XDR schema. The Base Path property provides the file path to the mapping schema.

The ClientSideXML property is set to True. Therefore, the XML document is generated on the client.

In the application, an XPath query is specified directly. Therefore, the XPath dialect {ec2a4293-e898-11d2-b1b7-00c04f680c56} must be included.

Hinweis:
In the code, you must provide the name of the instance of SQL Server in the connection string. Also, this example specifies the use of the SQL Native Client (SQLNCLI) for the data provider which requires additional network client software to be installed. For more information, see System Requirements for SQL Native Client.

Option Explicit
Sub main()
Dim oTestStream As New ADODB.Stream
Dim oTestConnection As New ADODB.Connection
Dim oTestCommand As New ADODB.Command

oTestConnection.Open "provider=SQLXMLOLEDB.4.0;data provider=SQLNCLI;data source=SqlServerName;initial catalog=AdventureWorks;Integrated Security= SSPI;"

oTestCommand.ActiveConnection = oTestConnection
oTestCommand.Properties("ClientSideXML") = True

oTestCommand.CommandText = "root"
oTestStream.Open
oTestCommand.Dialect = "{ec2a4293-e898-11d2-b1b7-00c04f680c56}"
oTestCommand.Properties("Output Stream").Value = oTestStream
oTestCommand.Properties("Base Path").Value = "c:\Schemas\SQLXML4\XPathDirect\"
oTestCommand.Properties("Mapping Schema").Value = "mySchema.xml"
oTestCommand.Properties("Output Encoding") = "utf-8"
oTestCommand.Execute , , adExecuteStream
oTestStream.Position = 0
oTestStream.Charset = "utf-8"
Debug.Print oTestStream.ReadText(adReadAll)

End Sub
Sub Form_Load()
 main
End Sub