>>>>>>>>>>>> Xanana Gusmao wrote (2006-12-12 04:08:39):
> On this page http://wiki.apache.org/db-derby/HibernateHelp
> it says:
>
> "Hibernate Annotations do not work because Derby does not allow a unique column
> to be nullable"
>
> Is this (that Derby's unique column must be non-nullable) still true
> ?
That's still true. UNIQUE constraint on nullable columns is optional
feature T591 in the SQL standard and not implemented in Derby. See
http://wiki.apache.org/db-derby/SQLvsDerbyFeatures.
For a longer discussion of the topic, see
http://mail-archives.apache.org/mod_mbox/db-derby-dev/200511.mbox/%3C20051102114053.GB7614@atum01.norway.sun.com%3E
--
Bernt Marius Johnsen, Database Technology Group,
Staff Engineer, Technical Lead Derby/Java DB
Sun Microsystems, Trondheim, Norway
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