Lack of object properties

If you want a UNSContainer object, you need to generate a UNSContainer key or go through the PK.

We used to do the mapping of the XObjectKeys in the P tables, but that had more disadvantages than advantages. Therefore it was abolished.

Generation of the key:

dim key As New DbObjectKey(Table.UNSContainer, "myUid")

I need to find UNSContainer object from XObjectKey of it.

I have replaced it with 

Dim Container as UNSContainer = Session.Source.Get(Of UNSContainer)(Query.From(Table.UNSContainer).Where(f.Comparison(Table.UNSContainer.XObjectKey, ContainerKey, ValType.String)).SelectNone)

and it's working as it should

I need to find UNSContainer object from XObjectKey of it.

I have replaced it with 

Dim Container as UNSContainer = Session.Source.Get(Of UNSContainer)(Query.From(Table.UNSContainer).Where(f.Comparison(Table.UNSContainer.XObjectKey, ContainerKey, ValType.String)).SelectNone)

and it's working as it should

You should use f.UidComparison instead of f.Comparison for UID and ObjectKey columns. Otherwise the SQL server will needlessly burn CPU time reencoding the contents of the effected column.