many-many relationship with mapping table

girubasp · **Joined:** Thu May 21, 2009 5:54 pm **Posts:** 2

I have two tables that are related via a mapping table. The mapping table actually holds the ParentKey & ChildKey. I mapped them without having to have a class for the Mapping table as said in http://codebetter.com/blogs/peter.van.ooijen/archive/2008/05/29/nhibernate-many-to-many-collections-or-mapping-is-not-one-table-one-class.aspx

In my case many objects relate to one child table.
Table1 ---->
Table2 ----> MappingTable ----> ChildTable
Table3 ---->

My mapping table contains "ParentKey" (table1_PK or table2_PK or table3_PK) and childKey (ChildTable_PK).

Now I have to add a "parenttype" column to the mapping table. How can i possibly do that?
Any help is appreciated.

wolli · **Posted:** Fri May 22, 2009 2:03 am

You need to model a class for the mapping table.

Table 1 1:* MappingTable *:1 ChildTable

kpursglove · **Joined:** Fri May 22, 2009 2:49 pm **Posts:** 2

Is it not possible to do this without mapping the 'link' table. I guess I'm missing something but as I currently understand it, if I have to a add a class for the link table then my object model starts to look like my database?

wolli · **Posted:** Mon May 25, 2009 2:44 am

Not that I know of. You have to map the link table.