Joins in fluent nhibernate

Question

Hi, I am using fluent nhibernate.

example:

i have 3 tables i.e.

CUSTOMER CustomerId pk CustomerName

PRODUCT ProductId pk ProductName

Cust_Product cust_prodId pk ProductId fk CustomerId fk

Now, I want to show customername, productnae

so, how do i write mapping class for the same.

i want to use

session.CreateCriteria(typeof("className")).List() like this. how do i do this..?

Answer 1

If you're looking for a full tutorial on how to do this, I recommend the FNH wiki or one of the many blog postings which can be found through Google.

However, you're trying to implement a many-to-many relationship here, and that seems to throw a lot of people off. Here's a rough guide:

On your Customer class, you'll need a collection like:

IList<Product> Products { get; private set; }

And similarly, on your Product class:

IList<Customers> Customers { get; private set; }

You start off a many-to-many map with the HasManyToMany function:

public class CustomerMap : ClassMap<Customer>
{
    public CustomerMap()
    {
        // other mappings

        HasManyToMany<Product>(x => x.Products)
            .WithTableName("Cust_Product")  // Specifies the join table name
            .WithParentKeyColumn("CustomerId") // Specifies the key joining back to this table (defaults to [class]_id, Customer_id in this case)
            .WithChildKeyColumn("ProductId")
            .FetchType.Join(); // Instructs NHibernate to use a join instead of sequential select
    }
}

Then repeat the process for the other side of the relationship (the Customers property on the Product class).