Hi all,

I need to get the sequence number to use in my application, before inserting it into the database. <generator....> is generating the sequence number only after i do session.save(somedto). Unfortunatly i have some not null values, hence i cannot just save an empty dto. Hence i have to get the sequence first before saving. Please help in what is the best way to do this.

thank you.
Gupta.

Hi Gupta!

Could you elaborate a bit more on your use case? I found it rarely necessary to get a primary key identifier as Hibernate would generate it to fulfil database restrictions. If your objects are mapped by Hibernate, than Hibernate is doing just that for you, ensuring, that database inserts occur in the right order.

In mixing legacy (JDBC) code with Hibernate I find it sometimes necessary to flush() the session early to force Hibernate to save the objects, and therefore assign identifiers I can use in the legacy JDBC areas of the code. But even than, my in-memory objects are ready to be saved (i.e. they are complete).

All the best,

René

Hello you must be more specific. What DB do you use and could you give your mapping.

Regards Sebastian

Thank to both of your for responding.

Currently, I am using MS SQL Server. But this system should be DB independent.

To explain in simple terms. I need to get have a unique reference number(for which i would like to use a sequence) and show it in the input page for the user to input. The input given by the user will be stored in database. Hence the sequence should be generated while generating the input page and stored in the database after user submission.

Thank you.

Hello Gupta!

I feel this is an odd requirement, but hey, it's your system. ;-)

Did you have a look at the generator type "assigned" ? (see section 5.1.4.5
http://www.hibernate.org/hib_docs/v3/re ... d-assigned)

All the best,

René

my ideas:
1)
separate your id and a "task number". Task number may be a separate field in a separated table, eg. a sequence or increment field; or a stored procedure generating numbers or ...
So you will have a separate mapping.

if the user starts the dialog, create the task number just before. You may have unused task numbers if the user does not save his form or if you do not delete unused task numbers.
2)
nearly as 1)
but you have a 1:1 relationship from task number to your task details.
3)
if you have differnent tasks have a look at inheritance mapping in the reference.

Regards Sebastian