I'm using the table-per-class-hierarchy design, as explained in the documentation. However, my discriminator is part of a joined table. I'm not sure how to accomplish this.

The easiest way to explain would be to extend the "Payment" example from the docs. The example has the discriminator (PAYMENT_TYPE) as a field in the payments table. I want to store my payment types in a separate table and join against them, but still be able to use the CashPayment, ChequePayment, etc. values as a discriminator.

Any ideas?

Thanks

Norman

try using a subselect in a discriminator <formula>

Thanks. I tried this, and it seems to work. With one hitch...

Hibernate is dynamically renaming my tables (Devices --> device0_), so I have no way of writing a formula that works. For instance...


... works for some queries but not others.

Any ideas? Thanks,

Norman[/code]

The formula should be straight SQL that you would write if you were using something other than hibernate.

i.e. we do the same thing as you're describing with:

@hibernate.discriminator formula="(select wt.WORKFLOW_EVENT_CLASS from WORKFLOW_TYPE wt where wt.WORKFLOW_TYPE_ID = WORKFLOW_TYPE_ID)"

I think the "missing" part from my query would be the last WORKFLOW_TYPE_ID should probably be this.WORKFLOW_TYPE_ID but I believe that hibernate will just imply this anyways.

Perhaps that's my problem. I'm using MySQL, and I don't believe it supports any magic keyword to refer to the outer table. In your example, "this" is your keyword. In MySQL, I would have to refer to the table name by it's name.

Since Hibernate is generating the query on the fly, and refers to the table by an alias, I cannot predict what table name to use!

Any other ways around this? I realize this is perhaps a DB-specific problem, but surely I'm not the first to tackle this.

Thanks for any ideas,

Norman

Hibernate parses the given formula and inserts its own aliases where approporiate. Any unaliased identifier is assumed to belong to the outer table.