Hi im working on a project using HibernateDaoSUpport from my Daos from Spring & spring-ws & hibernate & postgres who will be used in a national application (means a lot of users)

Actually, every exception from hibernate is automatically transformed into some specific Spring dataAccesException.

I have a table with a keyword on the dabatase & a unique constraint on the keywords : no duplicate keywords is allowed.

I have found twows ways to deal with with that in the Insert Dao: 1- Check for the duplicate manually (with a select) prior to doing your insert. I means that the spring transaction will have a SERIALIZABLE isolation level. The obvious drawback is that we have now 2 queries for a simple insert.Advantage: independent of the database

2-let the insert gone & catch the SqlException & convert it to a userfriendly message & errorcode to the final consumer of our webservices.

Solution 2: Spring has developped a way to translate specific exeptions into customized exceptions. see http://www.oracle.com/technology/pub/articles/marx_spring.html

In my case i would have a ConstraintViolationException.

Ideally i would like to write a custom SQLExceptionTranslator to map the duplicate word constraint in the database with a DuplicateWordException.

But i can have many unique constraints on the same table. So i have to get the message of the SQLEXceptions in order to find the name of the constraint declared in the create table "uq_duplicate-constraint" for example. Now i have a strong dependency with the database.

Thanks in advance for your answers & excuse me for my poor english (it is not my mother tongue)