Entity Framework or something else?

Question

I am just switching from C to C# and would like to invest sometime learning database work. I am overwhelmed with the options: Linq-to-sql, ADO.NET. nHibernate, EntityFramework, plain old sql (I am used to this). Since I have only limited 'learning' hours available (about 2.5 hours per day), where should I invest my time?

I don't want to learn something that will be obsolete next month or for which no one will hire me.

If I learn EF, will this knowledge be easily transferrable to nHibernate?

Update: I decided to start with nHibernate. While EF 4.0 has fixed many shortcomings, I don't have VS2010 right now and won;t have it for another 1 year. So nHibernate is the man for now.

Answer 1

EntityFramework is what Microsoft is showing as their proposed database technology. It incorpates a lot of what Linq-to-Sql does. I would start there along with ADO.NET. You'll encounter ADO.NET a lot as well.

Like the comment says too Linq-to-sql isn't being advanced anymore either.

http://msdn.microsoft.com/en-us/library/aa697427(VS.80).aspx#ado.netenfrmovw_topic2

Answer 2

Rather than pick something you think you might be hired for, focus on EF (perhaps) as a concrete example of a solution to the ORM problem as a whole. In spite of leaning EF your future employer might be an nHibernate house, or have their own home-grown solution. Learn EF, but use that experience to learn the ins and outs of ORM.

Answer 3

If you wish to explore Entity Framework, this series of Pluralsight videos by Julie Lerman demonstrates many of the basics you'll need to get going. As Kevin mentioned, Microsoft is putting less emphasis on LINQ-to-SQL and more on LINQ-to-EF.

Answer 4

NHibernate has greater flexibility in inheritance mapping, better integration with stored procs / database functions / custom SQL / triggers, support for formula properties and it just a more mature platform than EF 4.

Answer 5

Personally, I think NHibernate (plus FluentNHibernate and Linq to NHibernate) lets me keep the most sanity. In real world projects, managing a single EDMX file for a large data model in Entity Framework is really painful across a large team; in NHibernate, Fluent lets you separate things across multiple C# files, or the HBM xml format allows you do use multiple XML files. The last time I used the Entity Framework, that wasn't easy unless you had separate DataContexts for each model. (If that's changed in some way recently, I apologize for my ignorance). The most difficult thing about NHibernate will probably bite you in most ORM tools in one way or another: mapping object graphs to relational models is tricky. But you get an awful lot of control over things like lazy loading, parent/child relationships, and so on; mapping by convention is also a huge win if you're using Fluent.

But you won't go broke picking the tool that Microsoft is investing in; a lot of companies didn't even seriously consider using an ORM until the Entity Framework was released. Personally, I don't really want to work for companies that defer decisions like this until their vendor finds a passable solution, but the fact is, a lot of companies do (or will) use the Entity Framework.

There's absolutely nothing wrong with using the Entity Framework, although I suspect that if you used EF in anger for a real-world project for 4 weeks, and NHibernate in anger for about 4 weeks, with multiple developers on the project, there's a good chance you'd find NHibernate simpler. In my experience, EF looks much simpler at first, but gets hairier the longer you use it. NHibernate looks and feels much harder at first, but gets simpler and more obvious the longer you use it.

Answer 6

(sorry for the long post ahead, but I decided to try to give a bit of background to two of the main frameworks)

I'd like to add that using a non-Microsoft technology has the advantage of creating a larger birds-eye view of the problem and prevents you from locking yourself into that .NET + Entity + SQL Server cycle (even though Entity is database agnostic).

You might consider NHibernate. It's arguably one of the most mature open source ORM frameworks available. It is fast and it is used by large and very large enterprises. There also lies its greatest weakness: NHibernate is considered to have a rather steep learning curve. If you take this path, I can recommend the excellent book "NHibernate In Action" published by Manning.

Many of the weak points of NHibernate have been taken away from two sides: best practice ORM enterprise have been implemented in the S#arp architecture (downloads at Github now), which also covers fully automated mapping from database to MVC architecture. S#arp Architecture makes complex NHibernate scenario's a breeze (but still has a steep learning curve).

On the other side is the easy-configuration part through Fluent NHibernate, which creates a "one point of maintenance" situation: just code your entity objects in C#, call Config and the database is created if it doesn't exist. Saves you a hell of a lot of time. Fluent really makes working with NHibernate as it always should've been (and actually, as EF could've been).

Note that, unless it has changed recently, that Entity Framework requires changes to the database for the stored procedures, which is why I personally rarely applied it. Also, EF does not scale too well in enterprises unless you add a lot of effort yourself. NHibernate shines when you have an existing database, need it for large enterprises, or do not want to change what you've already created (incl. triggers, SP's, constraints).

From a learning perspective: as others have said, learning EF is a good start, it is rather easy and there's ample documentation. Smaller organizations are more likely to use EF because of the ease-of-use. Medium sized to large companies are more likely to go to NHibernate (and comparable enterprise-minded mapping systems). EF is rather new, NHibernate has a long history. Both have their merits. Both work well with LINQ. Both are (very) good to understand well and find a place on your CV.

Answer 7

Hi,

I'm in the same boat as you, I found the Summer of NHibernate series really useful.

http://summerofnhibernate.com/

Thanks -Hem