Hi there,

I try to realize a many-to-many-relationship in my bean. The database is as follows:



I just want to access a collection of users from a usergroup. So I tried this:



Since there is a limitation in the JSF library I use, I can't use a java.util.Set for "users". It has to be an array or a java.util.List. So I had to introduce this @IndexColumn annotation, but I don't know what this annotation is good for.

Has anybody a hint?

Thanks you very much in advance
Newlukai

i think hibernate needs this column because Lists enable you to access elements via an index.

This means the elements have a fixed order. A standard sql-querry doesnt guaranty you that, so an index-column is needed to create.

Thanks. Now I know what this IndexColumn is good for.
But what can I do to avoid creating such a column? For me it doesn't make sense to create a column to serve an implementation issue.
I have a unidirectional many-to-many-relationship and instead of a Set I want to have a List or an Array. This should be possible, shouldn't it?

EDIT: OK. It was my mistake. I switched to java.util.List and it worked. Perhaps the error message that is shown when you use an array without @IndexColumn should be changed? It told me that array/List have to define an @IndexColumn so I didn't try List.