Hi,

I have a column in my table with serial type. the problem is, that I need an id for my object and operate with this id BEFORE the object is saved. However, the hibernate assigns an id AFTER the object is saved.

so I have sommething like this:
TABLE mytable (
userid SERIAL )

and my object
class User {
Integer userID;
...
}

Somewhere I read that I can get the next value by SELECT nextval('tablename_serialcolumn_seq'), but it didn't work, my database (informix) couldn't recognize this command.

Any ideas how to get a value for my Integer property and stay consistent with serial column?

(please comment wheter you solution is thread-safe (the racing conditions are ok)

thanks a lot

anyone any idea?

Why do you want the id before you save? If it is because you want to put the id in another table/object, you don't need the id, as you can work with Hibernate to do the updating in the right order.

Sherman

Try this:

select Sequencename.nextval from systables where tabid=1

yes, I need it for that reason. I hava an object with ID1, and it contains another object, which ID is composed of parent object's ID1 and another number.


the problem is, that I didn't map that complex object in hibernate, but I mapped the plain properties of parent object, and then i mapped the properties of the child object. and if I want to save the parent object, I simply manually save the child, and than the parent

Should I add mapping of child object to the parent object? I'm not sure, It will work....

You are making life very difficult for yourself.

Have your child and parent have separate generated ids in your Hibernate mapping.

Then all you need to do is:

child.setParent(parent);
session.saveOrUpdate(parent);
session.saveOrUpdate(child);

This is not a legacy database you are using Hibernate with, is it?

Sherman

could you give me your email?
yes it's a legacy database, we have an old database schema to which we have to adopt our objects

You need to look into using composite-id. Check out the documentation and the forums to see how this is used.


Sherman