Re: [smartweb-devel] Smartweb Auth and problem with XDoclet/ Hibernate union subclass

[Roberto Lo G. <rlo...@sm...>]

Humm... I think you still need the Gaetano's vote, plus you haven't
voted yet....

2007/11/8, Stefano V <st...@gm...>:
> Thank you for the answers!
>
> When i have time, I'll change the code to the joined subclass in auth
> module...
>
> 2007/11/7, Roberto Lo Giacco < rlo...@us...>:
> >
> > The problem using sequence generator is some database doesn't support
> > sequences: the consequence will be an unsable auth module on those
> > databases.
> >
> > An analysis og pros and cons of the two choices could be more helpful.
> >
> > Joined Subclass
> >   Pros
> >     # Well known and supported by xdoclet without needing to be patched
> >     # Supported by all databases
> >     # Allows database constraints
> >     # Better performances if a list of Subjects is requested (only id and
> > display properties)
> >   Cons
> >     # Requires an additional Subject table
> >     # Full queries on Subject, User or Group needs a JOIN on twoor three
> > tables
> >     # Pessimistical locking need to acquire 2 locks
> >
> > Union Subclass
> >   Pros
> >     # Better performances on quering User and Group entities as no JOIN is
> > requested
> >     # No additional table exposed
> >     # Easier to query using plain SQL outside Hibernate
> >   Cons
> >     # Quering Subject needs a UNION, whatever infos you need
> >     # Same field on two tables
> >     # Needs sequence support on the database
> >
> >
> > Gaetano Perrone wrote:
> > >
> > > I delve into the problem and hibernate documentation says that identity
> > > generator strategy is not allowed in union subclass inheritance, indeed
> > > the primary key seed has to be shared accross all unioned subclasses of
> a
> > > hierarchy.
> > > The suggested approch for generating table  for concrete class is to use
> a
> > > sequence generator strategy instead of native.  With this approch each
> > > table defines columns for all properties of the class, including
> inherited
> > > properties. The limitation of this approach is that if a property is
> > > mapped on the superclass, the column name must be the same on all
> subclass
> > > tables. (Hibernate group is going to relax this in a future release).
> > > This means that a dedicated class tree sequence could be
> > > introduced....Otherwise i don't know what happens using the
> > > hibernate_sequence as sequence instead of generator native...
> > > What do u thing about it??
> > >
> >
> > --
> > View this message in context:
> http://www.nabble.com/Smartweb-Auth-and--problem-with-XDoclet--Hibernate-union-subclass-tf4761003s17546.html#a13625607
> > Sent from the SmartWeb Developers mailing list archive at Nabble.com.
> >
> >
> >
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