0 Replies Latest reply on Jan 15, 2007 6:23 PM by jörg maurer

    How to update entities depending on state in other entity

    jörg maurer Newbie

      Newbie case is:
      Entity bean A relates to entity bean B via "AtoB".
      Entity bean B has property "state"
      -) as enum with possible values {1,2}
      -) current value of 1 in database
      -) just updated (but not persisted) property in entity bean B to 2.
      Two users U1, U2 try to subsequently update the equal entity bean A.
      Condition for update is to update Entity A only if A.AtoB.state = 1 in database. So if U1 commits udpate before U2 commits his update, U2 should be notified of "User U1 already ...blabla".

      ? 1) What is the right solution to assure this condition with JPQL/EJB3.0? Pros/Cons?
      !) Use Update Query with following right refresh solution
      !) Use Select with write lock, then update
      !)...

      ? 2) How to detect if the update succedded/failed? Pros/Cons?
      !) EJB Exception thrown, what type of
      !) Update count = 0
      !)...

      Appreciate your help