Drop-Down unique values

[Ingo Wolfmayr]

Hi everybody,

is it possible to get list of unique values using the widget-form drop-down. I 
want a dropdown with the brandname of the PRODUCT entity.

<field name="brandName" title="${uiLabelMap.BrandName}">
            <drop-down allow-empty="true">
                <entity-options entity-name="Product" 
key-field-name="productId" description="${brandName}">
                    <entity-order-by field-name="brandName"/>
                                                                                
<entity-constraint name="brandName" operator="not-equals"  value=""/>
                </entity-options>
            </drop-down>
        </field>

Thanks for any hint.

Best regards,
Ingo