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

Using dynamic connection strings


There are cases where an application may need to change connection strings depending on some condition. This can be in the context of a multi-tenant application, or perhaps a database failover scenario. In this recipe, we'll show you how to switch NHibernate connection strings at runtime.

How to do it…

  1. Start a new console application project named DynamicConnectionString.

  2. Add references to NHibernate.dll, log4net.dll, and the Eg.Core model from Chapter 1, The Configuration and Schema.

  3. Add a reference to System.Configuration from the .NET framework.

  4. Set up App.config with a standard NHibernate and log4net configuration.

  5. Add the following DynamicConnectionProvider class:

    public class DynamicConnectionProvider : 
      DriverConnectionProvider
    {
    
      private const string ANON_CONN_NAME = "db";
      private const string AUTH_CONN_NAME = "auth_db";
    
      protected override string ConnectionString
      {
        get
        {
          var connstrs = ConfigurationManager.ConnectionStrings;
       ...