NHibernate map join table with extra column

Question

I have 3 tables: Workspace with PK IdWorkspace and other columns, Language with PK IdLanguage and other columns and join table WorkspaceFooter with multiple PK (IdWorkspace FK and IdLanguage FK) and extracolumn string Denomination. I cannot find a way to map those in Nhibernate, a way that WORKS.

How should I write in the .hbm.xml files? What should I map in Workspace? A collection, a list of WorkspaceFooter etc.?

Please keep in mind that for some reason the relationship in Workspace that points to WorkspaceFooter needs to be inverse="true". An update in Workspace must force an update in WorkspaceFooter too.

Thank you in advance.

Answer 1

You need to be clear about:

• the class model you need (derived from the business logic, not just the database model)
• Whether you really need a bidirectional relation

You could:

• map it as an independent entity in a list (which is the solution with the most management code required),
• map it as a composite element with the denomination and a many-to-one to the language. It also uses a specific class in C# for this. Probably the most straight forward solution.
• map it as a map (dictionary in C#), where the denomination is the key (given that it is unique within the same workspace and a typical way access the language),
• probably you can map it as a list and use filters to access only data of a certain denomination. I don't have experience with filters and I don't know what kind of troubles you may face.