This week's book giveaways are in the iOS and Features new in Java 8 forums. We're giving away four copies each of Barcodes with iOS: Bringing together the digital and physical worlds and Core Java for the Impatient and have the authors on-line! See this thread and this one for details.
I am working on an application what uses Hibernate to populate (initialize)a DB with a large web of interconnected objects. It has several many-to-many link tables, etc.. I don't have a problem with mapping the objects, but how to cleanly handle massive number of insertions using Hibernate's API.
I have followed the advice of the Hibernate docs and have a sythetic key assigned from a sequence in the DB. Now when I insert a duplicate object Hibernate has no problem inserting a new row in the DB with a new sequence id. If I give the Business Key a unique constraint an exception is thrown. Now I don't like the idea of finding out about a duplicate through an exception.
I was wondering what is the standard way that this situation is handled. Is it to first issue a Query (or get()) on the root object and every single member of its collections on each insert to make sure they don't exist and if they do reuse that object?
I know this is probably a very newbee question, but any guidance would be greatly appreciated.
This thread covers the downside of doing a query for a duplicate before performing the insert instead of using a unique index and responding to the exception. Long story short, there's a race condition that forces you to respond to the exception anyway, so you may as well put the duplicate-handling code in one place.