Hibernate version: 3.1 beta 1

Name and version of the database you are using: Oracle 10G

I am trying to make a bulk delete using the hql query

delete DtaPlatform where recordType =:recType

DtaPlatform class has some one-to-one, some one-to-many and some many-to-one relations. When I try to execute this query Hibernate throws a ConstraintViolation exception from a one-to-one related class of DtaPlatform.
Dtaplatform has cascade=all for all relations in its mapping.

This makes me think that bulk delete does not cascade to sub-objects.
Is that true?

Thanks in advance.