Reverse Engineering: ManyToMany configuration wrong?

Serethos · **Joined:** Thu Oct 04, 2007 12:22 pm **Posts:** 48

I used Hibernate Tools 3.1 GA and Eclipse 3.5 to reverse engineer a MySql5 Database using annotations. In case of a many-to-many association I am confused why the tools resolved them in a bad way so that I am assuming I have configured the process wrong.

There are the two tables 'Order' and 'Item' whose many/many-association is realized via the cross table 'OrderedItem'. I expected the tools to build the Order entity like this:

Code:

public class Order
{
 private Set<Item> items;
 ...
}

instead, the tools mapped the cross table directly:

Code:

public class Order
{
 private Set<OrderItem> orderItems;
...
}

The only option I saw was the "detect many-to-many associations" which does regarding to the manual:

Quote:

detectManytoMany (default:true): If true (the default) tables which are pure many-to-many link tables will be mapped as such. A pure many-to-many table is one which primary-key contains has exactly two foreign-keys pointing to other entity tables and has no other
columns.

As my 'Order' table has a composite key, this option shall (and does to my experience) no effect.

Did I oversee any option to _not_ map the cross table, so that the entities carrie only a collection of the original referenced entities?

max · **Posted:** Sun May 30, 2010 9:27 am

show the ddl for your "middle table"

if it doesn't have exactly two primary keys which forign key constraints relates to the two sides then it will not be noted as a many-to-many