Book Image

NHibernate 4.x Cookbook - Second Edition

By : Gunnar Liljas, Alexander Zaytsev, Jason Dentler
Book Image

NHibernate 4.x Cookbook - Second Edition

By: Gunnar Liljas, Alexander Zaytsev, Jason Dentler

Overview of this book

NHibernate is a mature, flexible, scalable, and feature-complete open source project for data access. Although it sounds like an easy task to build and maintain database applications, it can be challenging to get beyond the basics and develop applications that meet your needs perfectly. NHibernate allows you to use plain SQL and stored procedures less and keep focus on your application logic instead. Learning the best practices for a NHibernate-based application will help you avoid problems and ensure that your project is a success. The book will take you from the absolute basics of NHibernate through to its most advanced features, showing you how to take full advantage of each concept to quickly create amazing database applications. You will learn several techniques for each of the four core NHibernate tasks—configuration, mapping, session and transaction management, and querying—and which techniques fit best with various types of applications. In short, you will be able to build an application using NHibernate by the end of the book. You will also learn how to best implement enterprise application architecture patterns using NHibernate, leading to clean, easy-to-understand code and increased productivity. In addition to new features, you will learn creative ways to extend the NHibernate core, as well as gaining techniques to work with the NHibernate search, shards, spatial, envers, and validation projects.
Table of Contents (17 chapters)
NHibernate 4.x Cookbook Second Edition
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
Index

Eager loading with LINQ


Often, when we query for some set of entities, we also want to load some of the related entities. In this recipe, we'll show you how we can use LINQ extensions to eager load the child collections of our query results.

Getting ready

Complete the Getting Ready section at the beginning of this chapter.

How to do it…

  1. Create a new folder named EagerLoadingWithLinq in the project.

  2. Add a new class named Recipe to the folder:

    using System.Linq;
    using NH4CookbookHelpers.Queries;
    using NH4CookbookHelpers.Queries.Model;
    using NHibernate;
    using NHibernate.Linq;
    
    namespace QueryRecipes.EagerLoadingWithLinq
    {
        public class Recipe : QueryRecipe
        {
            protected override void Run(ISession session)
            {
                var book = session.Query<Book>()
                    .Fetch(x => x.Publisher)
                    .FirstOrDefault();
    
                Show("Book:", book);
    
                var movies = session.Query<Movie>()
                    .FetchMany(x => x.Actors)
            ...