updating many records (batch update) in hibernate

I have class A and class B. Now class A has Set of B.

class A{
 Set<B> bset //

}

bset.size() can be > 100 or > 500 etc

Now i want to change one filed of all B which corresponds to A

Eg:update B set Bfield = x where id IN (1,2,3);

1)What will be the query in hibernate? 2)1,2,3 ar开发者_开发知识库e ids of B (B.id).

3)How can i retrive all ids of B that corresponds to A in the format required by the query?

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If I understood you correct

update B set b.field = :newValue where b.parent = :parentA