Asp.net-mvc – ASP.NET MVC and ORM Selection

asp.netasp.net-mvcorm

We are getting ready to begin redevelopment of a large aging internal enterprise application. We have decided to use ASP.NET MVC, but under consideration is which Object Relational Mapping (ORM) to choose. There are of course a multitude of open source and paid ORM implementations available. However, NHibernate seems to hold the largest mindshare, while the Entity Framework is the new hotness from Microsoft.

While we are doing research and toying around with both we wanted to put it to the community as to which ORM (NHibernate, Entity Framework, or otherwise) they prefer and why.

Somewhat similar Stackoverflow Questions

What are you favorite .NET ORMs? (good list, but w/o justifications)
ASP.NET MVC + ORM (focuses primarily on Castle Project AR)
What object mapper solution would you recommend for .NET? [closed question]

Additional .NET ORM Reading

Best Answer

You should have a look at Sharp Architecture an ASP.NET MVC application framework which uses NHibernate.

I've used a few O/RMs in the past couple of years and there's no way would chose anything other than NHibernate.

It's the most mature.
It's got a huge set of features.
It's got a good community behind it.
It's got some fantastic ancillary projects such as Fluent NHibernate.

I don't know what more information people will be able to give you over and above in the questions that you have linked to.

Related Solutions

The “N+1 selects problem” in ORM (Object-Relational Mapping)

Let's say you have a collection of Car objects (database rows), and each Car has a collection of Wheel objects (also rows). In other words, Car → Wheel is a 1-to-many relationship.

Now, let's say you need to iterate through all the cars, and for each one, print out a list of the wheels. The naive O/R implementation would do the following:

SELECT * FROM Cars;

And then for each Car:

SELECT * FROM Wheel WHERE CarId = ?

In other words, you have one select for the Cars, and then N additional selects, where N is the total number of cars.

Alternatively, one could get all wheels and perform the lookups in memory:

SELECT * FROM Wheel

This reduces the number of round-trips to the database from N+1 to 2. Most ORM tools give you several ways to prevent N+1 selects.

Reference: Java Persistence with Hibernate, chapter 13.

Asp.net-mvc – Compile Views in ASP.NET MVC

From the readme word doc for RC1 (not indexed by google)

ASP.NET Compiler Post-Build Step

Currently, errors within a view file are not detected until run time. To let you detect these errors at compile time, ASP.NET MVC projects now include an MvcBuildViews property, which is disabled by default. To enable this property, open the project file and set the MvcBuildViews property to true, as shown in the following example:

<Project ToolsVersion="3.5" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <PropertyGroup>
    <MvcBuildViews>true</MvcBuildViews>
  </PropertyGroup>

Note Enabling this feature adds some overhead to the build time.

You can update projects that were created with previous releases of MVC to include build-time validation of views by performing the following steps:

Open the project file in a text editor.
Add the following element under the top-most <PropertyGroup> element: <MvcBuildViews>true</MvcBuildViews>
At the end of the project file, uncomment the <Target Name="AfterBuild"> element and modify it to match the following:

<Target Name="AfterBuild" Condition="'$(MvcBuildViews)'=='true'">
    <AspNetCompiler VirtualPath="temp" PhysicalPath="$(ProjectDir)\..\$(ProjectName)" />
</Target>

Best Answer

Related Solutions

The “N+1 selects problem” in ORM (Object-Relational Mapping)

Asp.net-mvc – Compile Views in ASP.NET MVC

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