Hibernate version: 3.3.1 GA, with Apache Derby Embedded 10.4.2.0

I started from the sample about inheritance in the book Java Persistence with Hibernate, with a table per hierarchy mapping strategy (see Fig 5.2 on P.199).

I extended the example by adding a RemuneratedAccount class that extends BankAccount.

RemuneratedAccount has a unique property, rate of type float.

So the hierarchy looks like:



The mapping provided is as follows:



Then, in the code of my application, I populate some instances of RemuneratedAccount and set a value for each property (id, owner, account, bankname, rate), including inherited ones, before saving and commiting them.

When I fetch my instances, the values for account and bankname (each one defined in BankAccount) are null. Every other property value is retrieved back with the right value.

When inserting, the generated JDBC statement is as follows:

insert into BILLING_DETAILS (BD_OWNER, RA_RATE, DISC, BD_ID) values (?, ?, 'RA', ?)

where we can see that columns BA_ACCOUNT and BA_BANKNAME are missing.

Did I do something wrong ? Can someone explain this strange behavior ?

Thanks in advance,

arnoth

Hi,

It looks like you want RemuneratedAccount to be a subclass of BankAccount, but your mapping shows it as simply being a subclass of BillingDetails.

You should nest the RemuneratedAccount subclass XML within the BankAccount subclass XML to tell Hibernate about the hierarchy.


Hope that helps.


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Stephen Souness

Hi Sounie,

Thanks for your answer.

I thought that the use of the extends XML attribute was sufficient to express the hierarchy.

I'll try this and tell you of the result.

yes it worked.

thanks alot.

So the right mapping is as follows:



But shouldn't Hibernate trigger an error because there is an inconsistency between the nesting of the hierarchy in the mapping and what is defined in the extends attributes ?