Please post comments or corrections to the Author online forum at
http://www.manning-sandbox.com/forum.jspa?forumID=295
1
Object/Relational Persistence in .NET
This chapter covers
.NET persistence and relational databases
Layering .NET applications
Approaches to implement persistence in .NET
How NHibernate solves persistence of objects in relational databases
Advanced persistence features
Software Development is an ever changing discipline where new techniques and technologies are constantly
emerging. As software developers, we have an enormous array of tools and practices available, and picking the
right ones can often make or break a project. One choice that is thought to be particularly critical is how to
manage persistent data, or put more simply, how to store, load and save data.
There are endless options available to us. We can store data in simple binary or text files on a disk. We can
chose different formats including CSV, XML, JSON, YAML, SOAP, or even invent our own format.
Alternatively, we can send our data over the network to another application or service, such as a relational
database, an Active Directory server, or a message queue. We might even need to store data in several places,
or combine all these options within a single application.
As you may begin to realize, managing persistent data is considered a thorny topic. Of all the options,
relational databases have proven to be extremely popular but there are still many choices, questions and
options that confront us in our daily work. For example, should we use DataSets, or are DataReaders more
suitable? Should we use stored procedures? Should we hand code our SQL, or let our tools dynamically
generate it for us? Should we strongly type our DataSets? Or, should we actually build a hand-coded domain
model containing classes? If so, how do we go about loading and saving the data to and from the database? Do
we use code generation? The list of continues...
This topic is not just restricted to .NET. Then entire development community has been debating this topic,
often fiercely, for many years.
Debate continues, but one approach that has gained widespread popularity is object/relational mapping, or
ORM. Over the years, many libraries and tools have emerged to help the developer implement ORM in their
applications. One such tool is NHibernate - a sophisticated and mature object/relational mapping tool for
.NET.
NHibernate is a .NET port of the popular Java “Hibernate” library. NHibernate aims to be a complete
solution to the problem of managing persistent data when working with relational databases and domain model
classes. It strives to undertake the hard work of mediating between the application and the database, leaving
the developer free to concentrate on the business problem at hand. This book covers both basic and advanced
NHibernate usage. It also recommends best practices for developing new applications using NHibernate.
Licensed to Jason Wilden <jasonwilden@internode.on.net>
