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Reading the Schema

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Most providers support the schema that is shipped with Active Directory. The schema contains class and attribute definitions. ADSI abstracts the schema in "Provider://schema". Each object carries the schema location in which its class is defined. You can use the IADs::get_Class property method to obtain this information.

To bind to the schema container on a particular domain, do the following:

Dim SchemaContainer As Object
Set SchemaContainer = GetObject("LDAP://Fabrikam/Schema")


hr = ADsGetObject(L"LDAP://Fabrikam/Schema", IID_IADsContainer, (void**) &pSchema );

To list information in the schema container, bind to the container and enumerate each object in the container as shown in the following:

Dim prop As Object
Dim obj As Object
Dim SchemaContainer As Object
Dim Class As Object

Set SchemaContainer = GetObject("LDAP://Fabrikam/Schema")
'Show all items in the schema container
For Each obj In SchemaContainer
     Debug.Print obj.Name & " (" & obj.Class & ")"
Next

'Show the optional attributes
For Each prop In Class.OptionalProperties
   Debug.Print prop
Next


IADsContainer *pSchema=NULL;
 HRESULT hr;

 CoInitialize(NULL);

 hr = ADsGetObject(L"LDAP://Fabrikam/Schema", 
                   IID_IADsContainer, (void**) &pSchema );

 if ( !SUCCEEDED(hr) )
 {
   return hr;
 }

 // Enumerate schema objects
 IEnumVARIANT *pEnum = NULL;
 hr = ADsBuildEnumerator( pSchema, &pEnum );
 pSchema->Release(); // This is no longer needed, since we have the enumerator already.
    
 if ( SUCCEEDED(hr) )
 {
   VARIANT var;
   ULONG lFetch;
   IADs *pChild=NULL;
   VariantInit(&var);
        
   while( SUCCEEDED(ADsEnumerateNext( pEnum, 1, &var, &lFetch )) && lFetch == 1 )
   {
     hr = V_DISPATCH(&var)->QueryInterface( IID_IADs, (void**) &pChild );
     if ( SUCCEEDED(hr) )
     {
       BSTR bstrName;
       BSTR bstrClass;
       // Get more information on the child classes
       pChild->get_Name(&bstrName);
       pChild->get_Class(&bstrClass);
                
       printf("%S\t\t(%S)\n", bstrName, bstrClass );
                
       // Clean-up
       SysFreeString(bstrName);
       SysFreeString(bstrClass);
                
       pChild->Release();
     }
     VariantClear(&var);
   }
 }

 CoUninitialize();

You can also bind to an object and get the schema location, as shown in the following:

Dim prop As Object
Dim dom As Object
Dim Class As Object

Set dom = GetObject("LDAP://Fabrikam")
Debug.Print dom.Schema
Set Class = GetObject(dom.Schema)
'Mandatory attributes
For Each prop In Class.MandatoryProperties
    Debug.Print prop
Next