Why nhibernate tutorial

Here is the test method. We still have to implement the three methods which query the database for objects. Let's start with the most easy one, the GetById.

First we write the test. Now that was easy. For the following two methods we use a new method of the session object. Let's start with the GetByName method. As usual we write the test first. The implementation of the GetByName method can be done by using two different approaches. Let's start with HQL. Implement HCQ as below this works as expected and returns a product entity. In the above sample I have introduced a commonly used technique when using NHibernate. It's called fluent interfaces.

As a result the code is less verbose and easier to understand. You can see that a HQL query is a string which can have embedded named parameters. Parameters are prefixed by a ':'. NHibernate defines many helper methods like SetString used in the example to assign values of various types to those parameters. If more than one record is returned by the HQL query then an exception is raised. To get more information about HQL please read the online documentation. The second version uses a criteria query to search the requested product.

You need to add a reference to NHibernate. Criterion on your repository page. Many users of NHibernate think that this approach is more object oriented. On the other hand a complex query written with criteria syntax can quickly become difficult to understand.

The last method to implement is GetByCategory. This method returns a list of products. The test can be implemented as follows. In this article I have shown you how to implement a basic sample domain, define the mapping to a database and how to configure NHibernate to be able to persist domain objects in the database. I have shown you how to typically write and test CRUD methods for your domain objects. I have taken MS SQL Compact Edition as sample database but any other supported database can be used you only have to change the hibernate.

Ee have no dependencies on external frameworks or tools other than the database and NHibernate itself. NET of course never counts here. NHibernate The object-relational mapper for. Documentation » Your first NHibernate based application. Your first NHibernate based application This page is converted from the old nhforge. First published by: Fabio Maulo on , Last revision by: mStyle on Your first NHibernate based application Wiki extracted from the original blog post of Gabriel Schenker Welcome to NHibernate If you're reading this, we assume that you've just downloaded NHibernate or installed it from NuGet and want to get started using it.

This tutorial will talk you through the following: Installing NHibernate Defining a simple business object class. Create an NHibernate mapping to load and save the business object. Configure NHibernate to talk to your local database.

Using Unit Tests to make sure the code is working correctly. This is what we're aiming for: But first things first [: ] Lets start by actually doing something with that ZIP file you just downloaded. Installing NHibernate If you've downloaded the NHibernate binaries in a zip file, all you need to do is extract that file to somewhere sensible.

Create Your Project Before we start building our application and business objects, we'll need to create a blank project to put them in.

Defining the Business Objects Lets start by defining a very simple domain. In a mapping file when referencing a domain class you always have to provide the fully qualified name of the class e. Product, FirstSample. To make the xml less verbose you can define the assembly name in which the domain classes are implemented and the namespace of the domain classes in the two attributes assembly and namespace of the root node. It's similar to the using statement in C. Domain; using NHibernate.

Cfg; using NHibernate. Framework; namespace FirstSolution. Configure ; cfg. AddAssembly typeof Product. Assembly ; new SchemaExport cfg. Generic; namespace FirstSolution. Generic; using FirstSolution. Domain; namespace FirstSolution. Domain; using NHibernate; using NHibernate. Cfg; namespace FirstSolution. Configure ; configuration. Save product ; transaction. IsNotNull fromDb ; Assert.

AreNotSame product, fromDb ; Assert. AreEqual product. Name, fromDb. Name ; Assert. Category, fromDb. Entities and mapping files are successfully generated and stored in the specified folders:.

Design ORM models faster. Download Buy now. Entity Developer. Download Buy Now. NHibernate Database-First Tutorial The following walkthrough describes how to generate a model from the existing database, manually add and edit classes and components, generate C code for the model.

Prerequisites In order to complete this walkthrough, you will need access to the database server you are using. Creating a Model from the Existing Database To create a model from your existing database, perform the following sequence of actions: In the Solution Explorer window, right-click the name of your project.

Click Add. On the Set up data connection properties page, set up the connection to the database. Click Next. On the Model properties page, define the settings of your model. Note: On the Model Properties page, pay attention to the following: Keep the Detect ManytoMany associations check box selected to automatically detect many-to-many associations. Keep the Detect Table Per Type inheritances check box selected to automatically detect inheritances of that type.

Using the Preserve columns details and Preserve columns SqlType and Default check boxes, you may preserve either full information about the column or only full information about the type to obtain a database-independent model.

After creating such a database-independent model, you can easily create a database on a different server using the Update to Database functionality. Select the required code generation template and click Next. On the final window of the wizard click Finish.

The model is successfully created: Mapping and Code Generation Setup This section explains how to set up mapping and code generation in NHibernate models. We will create the entities and mappings for our database and I will show you how to insert, update and select data from your database. Using C and the NHibernate library. NET platform. It provides a framework for mapping an object-oriented domain model to a traditional relational database.

Its purpose is to relieve the developer from a significant portion of relational data persistence-related programming tasks. NHibernate is a port of Hibernate.

Setting up NHibernate Entities The first thing I will do is create a class for each of my tables in the database. Smart ha! So now we have two classes Person and Car. As you can see a person can own a car. So if we were to create this in the database our selves we would end up with a Person table and a Car table the Person table would then have a foreign key to the Car table. Now we need to tell NHibernate how things map together. We do that by creating mappings for each table inheriting from the ClassMapping class.

Lets go though this step by step. The first Method I am calling in the constructor is ID this is how we define the primary key for our table. The first parameter is the name of the column in the Person class that is the primary key the second is how I would like to generate the new primary keys.

I have chosen to allow the database to do this by declaring the Identity column. The second method we are calling is used to define normal columns. It is called Property the first parameter is the name of the column in our person class the second is wither or not we want the column to be nullable. The third method we are calling is used to define reference tables.

It is used to define how we treat the parent child relationship.