12

If starting a new project what would you use for your ORM NHibernate or LINQ and why. What are the pros and cons of each.

edit: LINQ to SQL not just LINQ (thanks @Jon Limjap)

Gareth Jenkins
  • 2,606
  • 1
  • 19
  • 21
John Boker
  • 82,559
  • 17
  • 97
  • 130

6 Answers6

13

I have asked myself a very similar question except that instead of NHibernate I was thinking about WilsonORM which I have consider pretty nice.

It seems to me that there are many important differences.

LINQ:

  • is not a complete ORM tool (you can get there with some additional libraries like the latest Entity framework - I personally consider the architecture of this latest technology from MS to be about 10 years old when compared with other ORM frameworks)
  • is primarily querying "language" supporting intellisense (compiler will check the syntax of your query)
  • is primarily used with Microsoft SQL Server
  • is closed source

NHibernate:

  • is ORM tool
  • has pretty limited querying language without intellisense
  • can be used with almost any DBMS for which you have a DB provider
  • is open source

It really depends. If you develop a Rich (Windows) desktop application where you need to construct objects, work with them and at the end persist their changes, then I would recommend ORM framework like NHibernate.

If you develop a Web application that usually just query data and only occasionally writes some data back to the DB then I would recommend good querying language like Linq.

So as always, it depends. :-)

David Pokluda
  • 10,693
  • 5
  • 28
  • 26
  • 3
    "has pretty limited querying language without intellisense" is kind of misleading... NHibernate has HQL and Criteria APIs. Criteria is regular .NET code so you *do* have IntelliSense. HQL does not have intellisense. – Mauricio Scheffer Mar 09 '09 at 17:34
  • "limited querying language": there are very few cases where you can't express a sql query in hql or criteria. Mostly related to CTEs, which also aren't supported in LINQ-to-SQL (http://stackoverflow.com/questions/584841) – Mauricio Scheffer Mar 09 '09 at 17:37
  • Finally, there are easy ways to make the Criteria API more strongly typed, see: http://nhforge.org/blogs/149.aspx, http://bugsquash.blogspot.com/2008/03/strongly-typed-nhibernate-criteria-with.html – Mauricio Scheffer Mar 09 '09 at 17:39
  • I actually would agree w/ David's point about the querying language. While I wouldn't call it "limiting" per se, I would say that the convergence of experessiveness and intellisense support doesn't match LINQ; Criteria queries still depend on strings out-of-the-box. That said, you can LINQ w/ NHibernate now for many scenarios (not all). – Paul Mar 23 '10 at 18:16
  • update: HQL now has intellisense: http://www.felicepollano.com/2010/03/30/HQLEditorWithIntellisense.aspx – Mauricio Scheffer Apr 26 '10 at 16:56
  • If I could edit your answer I could change the "LINQ" header to "LINQ to SQL" -- LINQ alone is not the same. – Chris Charabaruk Dec 26 '10 at 04:03
  • 1
    fast-forward to 2011 : NHibernate now includes a pretty complete LINQ provider and also QueryOver in addition to HQL and Criteria APIs. So the "limited intellisense" argument is now effectively obsolete. – Mauricio Scheffer Dec 06 '11 at 22:28
10

Errr... there's LINQ for NHibernate.

Perhaps what you mean is which to use:

  • LINQ to SQL
  • NHibernate

I prefer NHibernate.

LINQ to SQL is fairly lightweight, but it's a little bit more tightly coupled to your data structure, as opposed to NHibernate which is pretty flexible in terms of the types of object definitions that can be mapped to your table structures.

Of course that's not to say that LINQ to SQL has no uses: this very website uses it. I believe that it's quite useful to get up and running in small applications where the database schema is not as massive.

Jon Limjap
  • 94,284
  • 15
  • 101
  • 152
  • 2
    well this website isn't "medium size" either, it's a fairly large .com so obviously LINQ to SQL works fine for .com or e-commerce .com type apps....I would assume. – PositiveGuy Dec 14 '10 at 05:55
3

Start with NHibernate is a bad idea. It shows a good performance only with ably settings. Try to use EFv4 for large projects and L2S (maybe 3rd-part products) for small and medium size. These products are more convenient and flexible than NHibernate and allow you to start quickly.

JackD
  • 597
  • 4
  • 7
2

not a complete list

LinqToSQL Pro:

  • better tool support
  • good linq provider
  • easy to start with when db-schema == classes -

Con:

  • not flexible (ie db-schema != classes)
  • only supports MS SQL Server
  • no cascading (save, update ... doesnt cascade to referenced objects)

NHibernate Pro:

  • a lot rdbms supported ootb
  • feature rich
  • very flexible for almost all corner cases
  • open source

Con:

  • not so easy to start with
  • not from MS
  • there are many tools, but you have to search for

Between the 2 ORMs

i would choose LinqToSql if:

  • db-schema == classes
  • only ever use MS SQL Server
  • shop only allows MS-Products

i would choose Nhibernate if:

  • richer objectmodel
  • legacy db-schema
  • DB other than MS SQL Server or support multiple
  • performance critical (i think NH has more features to optimise performance than LinqToSql)

NOTE: this is my personal view. I deal mostly with (crazy) legacy dbs and complex ETL jobs where the object model helps a lot over SQL.

Firo
  • 30,626
  • 4
  • 55
  • 94
0

The main drawback of NHibernate is the inability to make use of method calls. They cannot be translated to SQL. To circumvent that, you have to recreate expression trees which is difficult to do.

jonsca
  • 10,218
  • 26
  • 54
  • 62
Oualid KTATA
  • 1,116
  • 10
  • 20
0

I don't use (or even know) NHibernate, I just want to give my testimony: I use LINQ to SQL since about 2 years with MySQL and PostgreSQL databases (using DbLinq on Windows, using Mono on Linux and Mac OS X).

So LINQ to SQL is NOT limited to Microsoft products.

I can confirm that LINQ to SQL is very well suited for small and medium projects, or large projects where you have the absolute control of the database structure. As the reviews indicate, LINQ to SQL has some limitations that make it an inappropriate tool when there is no direct mapping between the database tables and the entity classes.

Note : LINQ to SQL doesn't support many-to-many relationships (but this can be easily achieved with a few code lines).

CedX
  • 3,854
  • 2
  • 36
  • 45