Null value in subclass's field.

For example have next objEntities:

Super :

• globalAttribute

Sub1 :

• sub1Attribute

Sub2 :

• sub2Attribute

where Sub1 and Sub2 are sub entities of Super entity, and table :

super:

• ID
• GLOBAL_ATTRIBUTE
• SUB_ATTRIBUTE

Then take records from db by entity "Super". Select Query filled "sub2Attribute" with null values in all objects of Sub2, when "sub1Attribute" filled with values from db.