title: How to mimic upsert behavior using Hibernate?
body: <p>I'm writing an application that sync's entities from a third party datasource into our own schema, with a transformation/mapping step in between.  I'm using Hibernate to represent and persist the entities in our own schema.  A problem I'm running into is that I have a unique multi-column key on one of my tables.  The behavior I would like to see is analogous to an upsert: when Hibernate goes to persist an entity and detects a unique constraint violation, it does an update instead.  We are using MySQL, which provides an INSERT ... ON DUPLICATE KEY UPDATE syntax, but I'm not sure how or if Hibernate can be made to make use of it?</p>
  
  <p>I suppose I could always try the insert, and if I catch an exception do an update, but that seems hacky and suboptimal.  Any tips on a clean way to do this?</p>