I have a problem. Imagine this data model:
[Person] table has: PersonId, Name1 [Tag] table has: TagId, TagDescription [PersonTag] has: PersonId, TagId, IsActive Since [PersonTag] isn’t just a simple many-to-many join table, I have all three entities created in nHibernate (exactly like they are in the data model). PersonTag, therefore, needs a composite-id, which I have mapped to a class like this:
<composite-id name='PersonTagKey' class='PersonTagKey'> <key-property name='PersonId'></key-property> <key-property name='TagId'></key-property> </composite-id> I want to traverse the object graph and be able to look at both the Person and Tag objects from a retrieved PersonTag object. So, I have properties on the PersonTag object to do that, mapped like this:
<many-to-one name='Person' column='PersonId' lazy='proxy' cascade='none' class='Person'/> <many-to-one name='Tag' column='TagId' lazy='proxy' cascade='none' class='Tag'/> When I try to create a PersonTag object and save it, I get an ‘Invalid index n for this SqlParameterCollection with Count=n’ error. I know this is because I’ve mapped the PersonId and TagId properties twice, once for the composite-id, and once for the many-to-one relationship. If I don’t map the many-to-one objects, then everything works fine.
Is there some way for me to be able to have a composite-id AND a many-to-one relationship based on the same column modeled in the same nHibernate entity?
Kay, here’s the answer. Little-to-no documentation on this:
This will allow you to create a composite-id made up of the inverse of a many-to-one relationship.
Good hunting…