What is it the best solution to manage the "cascade" ?

Implement it only in Hibernate mappings (ex. cascade="all-delete-orphan") or implement it only in database (ex. "foreign key cacade delete").

Thanks in advance.

I think that if you have the choice, you should let Hibernate control that.

I personally even prefer to let Hibernate create my database schema. It is a lot easier to maintain and it allows for easier testing using java memory database etc.

You do this by putting the parameter
<property name="hibernate.hbm2ddl.auto">update</property>
in your hibernate.cfg.xml

see doc for other values.

Hope that helps.

cascades in the database are generally much more efficient

It depends: if your application is the only application that accesses the database then you can do whatever you want, but it is seldom the case.
If many applications work with the same database ("shared DB pattern") then it is better to push as much functionality and checks as possible down to DB layer.

In this case it does not matter if .NET program or SQL script are trying to manipulate the data too– DB level checks will safeguard the data.

PS: I recommend using SQL script to generate and populate database with test data and do not use schema auto-generation.

If you let the db cascade, doesn't that leave orphaned records in hibernate's cache?

Theoretically it might. But when several different programs modify data in the same database then validity of cache is always questionable. Cache (especially 2nd level) requires careful planning

Firstly, thanks for your answers.

Personally I prefer to implement the cascade operations into db (efficiency reason and portability) and create db scripts manually or generated by some tools where I create also the data model.

But the other question is:
Implemeting cascade into db can be a source of conflicts with Hibernate persistence manager (error messages like "Inconsistent state of data..." or others) ?

No, as long as you tell Hibernate what is going on will cascade="delete" and on-delete="cascade". Read the documentation.