I have quite often come upon tables likes this: | | supplier articlenr size stock | ------------------------------------------ | SuppA 100 1 57 | SuppA 100 2 63 | SuppA 100 3 19 | SuppB 100 1 12 | SuppB 100 2 21 | SuppB 100 3 51 | | So supplier and article number is the composite key of the table. I want to map it to an entity that looks something like this: | | public class ArticleSupply { | | private ArticleSupplyID id; | private Collection<SupplyInfo> supply; | | // ArticleSupplyID holds supplier and articlenr | @Id @Embedded | public ArticleSupplyID getId() { | return id; | } | | //This has size and stock information | @OneToMany | public Collection<SupplyInfo> getSupply() { | return supply; | } | | } | (I know the code above is not correct but I hope it gives you the idea.) Obviously this is not possible since the datamodel is not normalized. This raises two problems: 1.) The ArticleSupplyID is not unique in the table. 2.) Both ArticleSupply and SupplyInfo are mapped to the same table. One way to deal with the situation is by creating a view for ArticleSupply which looks something like this: SELECT DISTINCT supplier, articlenr FROM mytable. Then you could use a composite key for SupplyInfo to get the collection from the original table. This should work (untested) but it is not a very elegant solution. Since not normalized data is so common there must be a better solution. Does anybody have an idea? Regards fhh View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3962675#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...