Nhibernate Lazy load on multiple columns

Question

If I set LazyLoad on multiple properties-columns with NHiberante and access those properties one after the other, would it query the database for each property?
Example:

public class Product
{
    public virtual int ID {get; set;}
    public virtual string Name {get; set;}
    public virtual string FullName {get; set;}
    public virtual float Price {get; set;}
}

public class ProductMap : ClassMap<Product>
{
    Id(p => p.ID);
    Map(p => p.Name).Not.LazyLoad();
    Map(p => p.FullName).LazyLoad(); // Redundant - I know...
    Map(p => p.Price).LazyLoad();    // Redundant - I know...
}

if I query the DB like this:

var product = session.Load<Prodct>(2);
if (product.FullName == "*" && product.Price = 111)

Will there be 3 queries

The Product entity
The FullName property
The Price property

or when NHibernate query the DB for FullName it will query all the columns of the row?

Diego Mijelshon · Accepted Answer · 2011-11-24 18:59:03Z

2

NHibernate will load all the lazy properties of an entity in a single query (you can try for yourself...)

The main use case for this feature is blobs.

Lazy references, on the other hand, are loaded as needed.

As a side note, session.Load does not query the DB; it just creates a proxy, which will be loaded lazily. Use session.Get.

edited Nov 24, 2011 at 18:59

answered Nov 24, 2011 at 16:19

Diego Mijelshon

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2 Comments

gdoron Over a year ago

This is what I see as well, so There will be two queries right? Hope this dissuction will be shorter then that are handling in other thread. ;-)

Diego Mijelshon Over a year ago

Yes, you'll have one query for the non-lazy properties, and one for all the lazy ones.

Firo · Accepted Answer · 2011-11-24 16:38:56Z

2

there will be 2 queries

The Product entity
All LazyLoaded Properties

answered Nov 24, 2011 at 16:38

Firo

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