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

[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??
> >
>
> --
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> 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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