Orm get only the id from child object

I'm new to orm, and I'm making some tests.

I've two simple object Artist and Art:

Artist.cfc

  // identifier

  property name="ArtistID" fieldtype="id" generator="native";

  // properties

  property name="Firstname";

  property name="Lastname";

  property name="Address";

  property name="City";

  property name="State";

  property name="PostalCode";

  property name="Email";

  property name="Phone";

  property name="Fax";

  property name="ThePassword";

  /* one artist can have many... */

  /* return an array of Art objects */

  property name="Art" fieldtype="one-to-many" cfc="Art" fkcolumn="ArtistID" type="array" orderby="Price Asc";

Art.cfc

  // identifier

  property name="ArtID" fieldtype="id" generator="native" ;

  // properties

  property name="ArtName" ;

  property name="Description" ;

  property name="Price" ;

  property name="LargeImage" ;

  property name="IsSold" ;

  property name="Artist" fieldtype="many-to-one" fkcolumn="ArtistID" cfc="Artist"; 

When I try to get an artist:

   artist = EntityLoadByPK("Artist", 1);

I get a response with a struct with all the artist property, and an array of child art with all properties. (I have serialized in the example)

{"ArtistID":1,"Firstname":"Leonardo","Lastname":"Da vinci","City":"NewYork","Art":[{"ArtID":1,"ArtName":"landscape","Pric e":"1500","IsSold":"false","Artist":null},{"ArtID":2,"ArtName":"landsc ape","Price":"1500","IsSold":"false","Artist":null}]

I would like to retrieve not all the properties of child art, but only the primary key. Is this possible with Orm?