index column updates problem

Joe_1 · **Joined:** Fri Aug 17, 2007 11:12 am **Posts:** 2

Hi all,

I have an indexed collection mapped (as part of another entity) like this:

Code:

<list name="tournamentSamples" table="USER_TOURNAMENT_SAMPLES">
         <key column="USER_ID"/>
         <list-index column="SAMPLE_INDEX"/>
         <one-to-many class="prt.TournamentSample"/>
      </list>

When the collection is updated in a new session after several changes (add, remove, modify) have been made to it while it's in the detached state, ALL the database records of the collection are updated to make the index column a progression of consecutive integers starting with 1.

Is it how it is supposed to work? or am I doing something wrong?
I am new to Hibernate. The DOC says indexed collections are fast.

What is the purpose of the index column? If one would write the (functionally equivalent) schema by hand, in plain SQL, he/she would not need index column at all.

BTW, I can't use a set instead of a list because there is no unique"business" key exist for samples.

Thank you,
Joe

kochcp · **Posted:** Fri Aug 17, 2007 1:38 pm

hibernate defines the list collection as an ordered collection, based on the index column you need to define and use. If you don't need it to be ordered, and can't use a set, use a bag

Joe_1 · **Joined:** Fri Aug 17, 2007 11:12 am **Posts:** 2

Thank you, Chris.

Bags was exactly what I needed. One column less.

But the updates of all records were still there. I tracked down the problem to not entirely correct implementation of the setter method for the collection. The code looked very harmless (the commented out version), but was enough to break something in Hibernate:

Code:

   protected void setTournamentSamples(List<TournamentSample> x) {
      tournamentSamples = x;
      /*
      if (x == null)
         return;
      tournamentSamples = new ArrayList<TournamentSample>();
      for (TournamentSample s: x) {
         if (s != null)
            tournamentSamples.add(s);
      }
      */
   }

As soon as I made it a one line assignment, everything started to work as expected. I guess setter methods cannot be anything else than an assignment? (what Spec or Convention say that?, - could not find it anywhere).

You know I had to use those null checks because the Hibernate was giving me lists with null elements at some point.

Thanks again,
Joe