not-null integrity must be checked for DML statements and not for objects

This issue somehow relates to but is of much broader scope and pointing out a different aspect.

Currently Hibernate checks the not-null constraint integrity persisting any object already on the object level (which is a quite early point in time; for loading objects, this might cause analoguous problems).

The not-null XML attribute, however, is part of the <column> tag and therefore is assumed to match the characteristics of a column and not a mapped object property!
I am facing severe problems with the current behaviour, as the not-null check is performed even before
any nullSafePut() method is executed for a customized Hibernate type, or even before any the any PreInsertEventListener / PreUpdateEventListener has a chance to transform null-values for properties to non-null values for database columns.
Effectively, the flexibility to handle different nullability characteristics between columns and their mapped properties is thus reduced to zero.