I am using hibernate whith MySQL

I have an User object containing an Address object as reference (FK)
I am trying to insert an User object into the table.
For my point of view, Hibernate should check to see if Address object from User exists in the table address and if negative an specific Exception must be thrown.
If not so, I must do an extra find for Address before inserting in order to preserve the data integrity.

Other thing , about Unique Keys checks: Supose I have 2 unique keys in User object: userName and emailAddress.
When inserting a record which contains a duplicate value for one of those keys, how should I know wich of the fields are in fact duplicated only by looking at thrown Exception and not doing an extra find before insert?

Which is the best practice for those 2 cases?

Many thanks,

Florin Marcus.

The best practice is to use a database that implements foreign key constraints. For example, MySQL with innodb tables.

There is no way in the world that Hibernate should issue an SQL select to "check" that every associated object exists. Thats insane. A system like this could not possibly perform well.

Your first assumption is half true, and it works like you would expect it. But because you haven't shown any real problem (exception, mappings, code), we can't help you here.

Your second question: How would you do it without Hibernate?

Wow! That was fast! Finally a forum which really works!

Many thanks for clearing this up.

Best Regards, Florin Marcus