Hello,
I'm asking a question already asked a few years ago:
http://groups.google.be/group/comp.lang.java.databases/browse_frm/thread/c3a1045674b6b65f/c3aa99a30b22c8e6?hl=nl&lnk=gst&q=%22many-to-many%22&utoken=DT02DTsAAAAYHYTsDrEdq7-NnfRgl-Nk4GfRPBFGhDGPHFrvVDkRvgz1eTbjLK36WL5svdAfvL03TRB4SbQHh5KfXKICx3ka
When your middle table (that which relates your 2 tables
through a many-to-many relationship) contains more than
the A_ID and B_ID columns but also -for ex.- DATE columns
etc.- is there a way to deal with this extra info with some
more config in your .hbm.xml files or do you really need a
supplementary class to handle this data ?
When you have no more than the 2 ID columns to deal with,
the following mappings are enough:
<set name="events" table="PERSON_EVENT">
<key column="PERSON_ID"/>
<many-to-many column="EVENT_ID" class="Event"/>
</set>
in a file and
<set name="participants" table="PERSON_EVENT" inverse="true">
<key column="EVENT_ID"/>
<many-to-many column="PERSON_ID" class="Person"/>
</set>
in the other .hbm.xml file... And no specific class for the
PERSON_EVENT database table is required - but when this
table contains other columns, is there no way but to create
another class to play with this extra columns ?
In advance, thanks.
Regards,
Spendius
