NHibernate (Fluent) Lazy Loading Not Working

Question

I am attempting to use NHibernate to generate a model for a very odd database. The tables themselves have primary keys for show only, all the actual relationships are on unique columns. For example, a product table with a product id primary key and a unique product name column. Another table, demand, has a product name column and that defines the relationship. I know this situation isn't ideal but it's out of my control.

At any rate, I was able to use Fluent NHibrenate to map product to demand, but I cannot seem to get the entity to lazy-load.

public class Demand
{
  public virtual DemandId { get; set; }
  public virtual Product { get; set; }
}

public class DemandMap : ClassMap<Demand>
{
  public DemandMap()
  {
    this.Table("Demand");
    this.LazyLoad();
    this.Id(x => x.DemandId);
    this.References(x => x.Product).PropertyRef(x => x.ProductName).LazyLoad();
  }
}

Does anyone have any insight into why lazy loading is not working? I know it is not because I can see the product being fetched along with the demand in the SQL profiler.

So, it's joining to the product when you Get<Demand>? Can you show the sql? — dotjoe
– dotjoe, Commented Oct 18, 2012 at 20:07
Check out this link, propertyref stackoverflow.com/questions/4888140/… — BlakeH
– BlakeH, Commented Oct 18, 2012 at 20:09
dotjoe it's not actually joining, its doing an entirely separate query to get product, which is even worse really. — user653649
– user653649, Commented Oct 18, 2012 at 20:12
seems like Lazy loading is not available with property-ref stackoverflow.com/a/1649547/40822 — dotjoe
– dotjoe, Commented Oct 18, 2012 at 20:17
For your Product map, you might be able to try Id(x => x.ProductName).GeneratedBy().Assigned()...and let the legacy db generate the actual primary key. But, this might only work with an identity id. — dotjoe
– dotjoe, Commented Oct 18, 2012 at 20:31

Rafał Developer · Accepted Answer · 2012-10-18 22:37:56Z

1

My idea (Maybe you can try use "HasMany" there is example but you can read something about this):

First class

public class Demand
{
  public virtual int DemandId { get; set; }
  public virtual int Product { get; set; }
  public virtual IEnumerable<NewClass> Name {get; set;} 
}

  this.HasMany(x=> x.Product).Column("Product_id").not.nullable;

Second class

public class NewClass
{
  public virtual Demand Product_id {get; set;}
}

this.References(x => x.Product).Column("product_id).not.nullable

answered Oct 18, 2012 at 22:37

Rafał Developer

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