Update Data Extension Field to NULL using WSProxy

Question

I'm trying out the new WSProxy API for server-side javascript. I haven't been able to update a Data Extension field to NULL when it already contains a value.

Let's say "Student" is a nullable field. Putting this into the Properties array passed to the updateItem method doesn't clear out a value already stored in the Data Extension:

{
    Name: 'Student',
    Value: null
}

Neither does leaving the Value property out entirely:

{
    Name: 'Student'
}

The SOAP API documentation makes reference to a NullAPIProperty object to use in this circumstance, but I can't figure out how to pass that kind of object to WSProxy or get that API to create it. (Creating an object using Platform.Function.CreateObject() throws an error; that's a different API).

Answer 1

There's a hidden feature of WSProxy to allow you to do this!

If you were to write the raw SOAP call to set the value of a field in your DE record to NULL, you'd write it like this:

       <Property xsi:type="NullAPIProperty">
          <Name>StoreNumber</Name>
       </Property>

Notice, there's no value, but there is a type attribute on the Property element. You have to set that NullAPIProperty attribute on your property in the WSProxy call. To do that, you use a special notation: __Type__

So, you'd write your null property like so:

{
    Name: 'Student',
    "__Type__": 'NullAPIProperty'
}

The attribute notation is unfortunately not currently documented, but I'll see if I can contact someone who can get it on the help site.