Hello everybody,


I'm working with an Oracle 8 database which provides sequences to create unique primary key.

I have a POJO class "AideFinanciere" with a String type identifier field "aideCode" mapped to a VARCHAR2 column. I would like to use the sequence id generator of the database by declaring in my mapping :

(1)
<generator class="sequence">
<param name="sequence">seq#24</param>
</generator>

The problem is that the sequence generator returns a long value and that the id property is a String (it throws an exception "this generator returns a long, int, short"). I can't change the database column type because another application is working with it.

The other application retrieve these sequences numbers using to_char () with SQL request :

(2)
select to_char(seq#24.nextval) from sys.dual

But I don't know how to write a query for a sequence using Hibernate.

Does anybody knows how to access to a sequence next value with an HQL request or a trick to cast the long id generated by the hibernate generator to a String?

Thanks,
Eric

hibernate version : 2.1


[color=olive]the exception in case (1) :

DEBUG [http8080-Processor2] (AideFinanciereBO.java:53) - numSequence : 24
DEBUG [http8080-Processor2] (AideFinanciereDAOHibernateImpl.java:95) - AideFinanciereDAOHibernateImpl : insertion aide financi

Just write your own generator extending or similar to SequenceGenerator. Should not be too difficult.

Thank tou for your reply,

Tell me if I've understood you right :

I'm gonna change the generator to "assigned"

write a public String getSequenceNextValue(String sequenceName) method in SeqDAO

In that method I will instantiate a SequenceGenerator

configure it :

configure(Type type, Properties params, Dialect dialect)

and then generate the identifier :

generate(SessionImplementor session, Object obj)

and take the String.valueOf() the generated identifier
to return it.

Is that correct?

But how to configure the Sequence generator? What arguments should I pass to the configure and generate methods?

If you can help me ,thanks

No.

You write a class that extends net.sf.hibernate.id.SequenceGenerator, which ovverrides generate() and does return super.generate().toString() or something. Then you use

<id ...>
<generator class="yourclassname">
</id>

Just look at the source of other generators to get an idea of how it works.

Hello Micha

Hello Micha

Nice that you got this solved. And thanks for posting the solution.

How is this the right solution? sql member is private in SequenceGenerator