When Linq-to-Sql was first released, I used it quite a lot for small and medium sized projects where a true multi-tier architecture wasn't required.
NHibernate, Small Middleware, Overkill
Where I work, we now almost exclusively use NHibernate for true Domain Driven development.
I'm working on a small temporary (a lifetime of probably a year, maybe less) middleware component where NHibernate feels slightly overkill in terms of configuration and keeping the entities up to date. Especially because I haven't got any control over the DB, it sometimes changes, and it's a little bit "legacy".
Some changes were recently made to the DB, and the NHibernate mappings are not very complete.
Linq-to-Sql? Or EF?
I thought it might be easier just to rip out the IRepository implementation I have and replace it with a Linq-to-Sql implementation. Then I can just use lambdas for my simple queries, and just drag and drop the tables in.
RAD But Dead?
In this scenario the RAD elements of Linq-to-Sql make sense. But it's essentially old technology. Should I not use it? I've never used the Entity Framework. Should I use that, is it as easy and quick to use?
cheers
Is it still OK to use Linq-to-sql?
Yes. It is OK to use any technology which allows you delivering the product in time, with required functionality and quality. You can still find projects using ASP, ADO, VB6. One reason why Microsoft technologies have very hard time in many international corporations is that their products have very short lifetime. Linq-to-sql was on the market less then 2 years and was deprecated by Microsoft but companies / community argued about that and Microsoft changed their strategy little bit. Linq-to-sql doesn't have new features but it is still supported and a fully functional technology.
Will Linq-to-sql or EF solve your problems?
It depends. Perhaps yes and perhaps no. Don't believe to marketing announcements about RAD. Sometimes I feel that people think that RAD is about designer. No. Tools supporting RAD are about well defined API which is easy to understand, easy to use and doesn't contain unexpected behavior (Principle of least surprise) - you will use the API to quickly prototype the application but it still requires understanding and practice. NHibernate's mapping is still prototyping when you compare it with manually doing whole data access. We can even follow the basic rule of good framework: Easy things are easy to do and hard things are possible. That is something that NHibernate accomplish much better then EF or Linq-to-sql.
If you know NHibernate but you don't have any real world experience with EF or Linq-to-sql, you can be sure that neither Linq-to-sql or EF will increase your productivity in first one or two projects where you use it. If you don't have too much experience with NHibernate changing to EF or Linq-to-sql will probably don't cause temporary lose of productivity.
I also don't think that EF or Linq-to-sql will generally help you in situations where database changes. As I remember Linq-to-sql designer doesn't have update mapping functionality at all and because of that it is very often used completely without designer so you must still manually modify mapping. EF's updating model from database can be helpful here but it is not a silver bullet. Some updates can require manual modification of EDMX file (huge XML).
At last be aware that NHibernate's mapping features are much more powerful especially when working with legacy databases. Linq-to-sql's mapping features are very limited, it is mostly 1:1 mapping of tables to classes with some exceptions (basic TPH inheritance). EF offers more complex mapping features but it somehow expects a correct design of the database.
If you (and your coworkers) are comfortable with NHibernate, then it should be just as RAD as Linq to SQL. There's no reason not to use L2S as long as you understand it's not going to get much in the way of updates and improvements from Microsoft, but in my experience if you know how to use both frameworks already, no need in re-doing the work just because L2S might be a little more RAD
Some good discussion on NHibernate vs L2S/EF
Entity Framework vs LINQ to SQL
MS Entity Framework VS NHibernate and its derived contribs (FluentNHibernate, Linq for NHibernate)
in your specific case, you should go with technology you are most comfortable with. Though Linq2Sql is relatively straight forward - and build right into the language - it does have a slight learning curve and its own set of gotchas!
Related
I am stating a new project that needs to be portable and in some scenarios will have 100's millions of entities.
Now with Azure getting hadoop that of course got my attention for the big data scenario. But I also have the small data scenario under 1 million rows.
Entity Framework code-first is they way I see designing this but needing hadoop in the mix of course may complicate things (Entity Framework of course been used to give simpler storage providers for the smaller data sets)
Now the question is does anyone have experience in this mix?
Can anyone recommended if this is a good approach or not, if not is there a better way?
Working on a reasonably large system based on Entity Framework Code First, with the caveats that I have been working with EF4 and cannot upgrade to 5, that your mileage may vary and the outcomes are going to be strongly affected by what you intend to do, my experience has been that EF doesn't handle large amounts of data tremendously well, it is quite inflexible, so if you need to change its standard behaviour in some way there is a good chance you are going to end up having to hack some nasty workarounds, and performance isn't amazing. If you want to do things that aren't exactly the things that EF expects you to do, then you can run into walls.
If I was thinking of designing a relatively simple/small scale Asp.Net MVC setup, I think EF is a really good choice. For a larger scale operation where you need more flexibility or you are planning to go beyond basic operations you might find that something like NHibernate works better. I don't have experience with that, but colleagues who have worked with both tend to prefer NHibernate. ( Brief article on the comparison - a bit old so EF has addressed some, but not all of the points there. It is also different by design of course. )
It may be that for more high-traffic or unusual stuff you need to roll your own data access anyway just to achieve the right performance or be able to find the right data. Unsquestionably, if you are planning to try working with EF I strongly recommend some serious prototyping just to ensure it can do what you need.
Because of specifics of my current project, I have to keep using .NET 2.0. Are there any Entity Framework-like ORMs for .NET 2.0?
I'm absolutely OK with non-LINQ interface. Syntax like users.Where(u => u.Age > 100).Count() is fine.
I need to use DB-first approach: I already have a DB with about 30 tables and just considering the ways of simplifying work with it. So, I'd really appreciate if it's possible to generate the required code from existing DB.
It's also OK if it won't generate all the required code but provide the way to describe DB structure manually (using attributes, for instance). Basically, I just want to be able to build more or less sophisticated queries without messing with real SQL, SqlParameters and DataSets/DataTables with all these int.Parse(row[12].ToString()) (that's a legacy code I'm trying to get rid of)
Also, that would be great if I'm be able to "override" some particular "queries" with calls to existing stored procedures.
The most important is p.2 - DB first. Is there anything of this kind? Or am I absolutely wrong with my thoughts? Will appreciate any ideas.
Your best option is to check out NHibernate. Many (most?) people consider consider it more feature complete and powerful than EF 4.1, plus there are plenty of resources here on stackoverflow and the rest of the web to guide your development process.
Be sure to look into Fluent NHibernate to make mapping from your database to C# objects easy. The alternative of editing XML files is complex, clunky, and time consuming.
Note that you might need to use an older, but still completely functional, version of NHibernate that is compatible with .NET 2.0 (I think, but am not positive, that the more recent versions require .NET 3.5).
There is plenty of available ORMs but some of them are commercial (LLBLGen Pro). The good choice for you is probably NHibernate 2.1 (I think NHibernate 3.x requires .NET 3.5).
You should also thing about moving forward to a newer .NET version. Starting a new development on .NET 2.0 should be avoided and involving a new technology to existing old code base IMO spoils application's architecture and maintainability.
Edit:
So, I'd really appreciate if it's possible to generate the required code from existing DB.
The most important is p.2 - DB first.
ORM and code generation are two different areas. DB first doesn't mean code generation - it means mapping to existing database without needs to change the database. It is not point of ORM to generate code for you. The point of ORM is to allow you to map DB to classes and abstract querying. If the most important point for you is code generation you should look for something else then ORM. NHibernate doesn't have such code generation included but there are some additional projects which add similar features.
I was surprised to find a public letter proposing a vote of no confidence in the entity framework (see http://efvote.wufoo.com/forms/ado-net-entity-framework-vote-of-no-confidence/)
Would the reasons stated in the letter keep you from using the current version of the entity framework? Would you rather wait for v4.0? Or rather use another ORM?
The current version of EF is definitely not perfect, and has lots of gotchas and drawbacks. I probably wouldn't use it right now - but the upgrade path to EF v2 (or is it EF4?) sure looks pretty rosy!
complete persistence ignorance - you can use your straight up POCO classes
deferred loading configurable as an option
much improved designer with support for pluralization/singularization (even in multiple languages!)
ability to do "domain first" design and create database from your model
ability to have self-tracking entities across multiple layers that allow you to send data to the client and get back changes and apply them to your entity context
All in all, EF v2 looks very promising and I'm very eager to give it a serious spin. If it really keeps all the promises out there right now, it's definitely a winner!
Check out the ADO.NET team blog for a flurry of recent blog posts on EF v2.
Marc
Another ORM.
Don't get me wrong you should get flamed with responses, but currently only nHibernate is functionally complete.
I'm a TDD fan, so want an easily testable POCO ORM solution. If that's your bag then EF3.5 is out. EF4.0 is introducing it (http://blogs.msdn.com/adonet/archive/2009/05/21/poco-in-the-entity-framework-part-1-the-experience.aspx) , but it still has at least 1 big drawback -> doesn't support inheritance.
NHibernate is more complete, but EF could be easier to use. As ever, best tool for the job... but if it's an Enterprise-scale TDD developed app, go nHibernate.
Also -> there's a profiler that makes nHibernate dev much easier -> http://www.nhprof.com/
I tried using it for my current project, which basically involves rewriting our current mess of a data layer.
It just doesn't work.
First, if you're trying to base an Entity off of a View, the designer tries to force every NOT NULL property to be an entity key... which is pretty much never what I wanted. To work around that you have to edit the xml in at least two places, and do it every time you add an object because it refreshes and re-adds the EntityKey properties. Must specify mapping for all key properties in Entity Framework?
Second, when you are creating associations you MUST use every entity key - How can you make an association without using all entity keys in entity framework?
Those two things held me up for 3 days, then I went back to Linq to SQL and had it done in a couple hours. (Well, at least the part of the system I was struggling with... ) I don't know if those are in the Vote of No Confidence, but it's just not ready in my opinion.
Also with the lack of answers I got here on every EF question I've asked, I have to assume current usage is so low that getting help and support is going to be difficult... which is possibly the BIGGEST reason not to use something.
Let's hope the next version is better...
EDIT: OUr current plan is to stick with Linq 2 SQL (I have to finish a project by Friday) and then evaluate all the other ORMs to see if anything else is better. The other developer hates L2S for the record, but I've never had any major problems using it...
EF has some rich design time support, but I have to agree that nHibernate is the way to go, despite the learning curve. If you need to make something fast and don't care about TDD or serialization (which is a large weakness of all of MS's ORM offerings) go EF.
Well My experience of Version 1 was interesting. I wanted to use POCOs but it didn't support it. After reading around I came across some code from a bod at microsoft that did this.
It was a bit messy to generate the code but on the whole this part of the process was not so bad.
A real nasty part that I came across was the lack of Concurrency checking built in, for N-tier development. You have to manage this yourself which after looking at the problem was not so bad, especially if you want to hand back the versioning back to the client for user intervention.
Second nasty and absolutely stupid thing missing was the IN keyword for LINQ queries. Not supported and so needs to be worked around. I found a solution but was a real mess bringing in some other code that quickly patched up the omissions.
Would I use EF 4.0 (2.0). Yes, absolutely, why not? In fact on stage 2 I will be using this. It looks like it supports POCOs, it looks like my concurrency model will move straight across with no problems (basically delta copy stuff). Its all good so far and I hope this time round that the Big guys at Microsoft have seen the errors of their ways and provided a solution that works.
If your buying into entity development and the whole Concept Model first thing, then its the only way to go for a complete Microsoft solution. Although the stuff being done on the M language might eclipse the idea and move the whole modelling thing back to the Database.
If you not buying into the Entity stuff then I would strongly go Enterprise Library. Its a proven technology that works every time built on a solid code foundation and Database centric paradigm. I would also go this route if you think that Stored Procedures are the bees knees and like what they bring to the table.
If your feeling really exotic and feel a bit frisky I would go with a NO-SQL approach such as CouchDB. This however does take some getting used to. Its damn weird and feels really really wrong. But things get developed in super quick time and the solutions seem to be robust and faster than expected. I would not got for this type of solution though if your big into Normalization and think that it can be applied to a NO-SQL approach. The whole model needs to be shifted on its head and the application will be needed to be modelled in a way that is driven by the technology applied.
I find the CouchDB way a bit dirty and very very wrong. But it has so many compelling reasons to use it, that I think it will seep into the psyche of every programmer, and it will definitely go mainstream in the next couple of years.
My biggest gripe still with the whole Entity thing though even in the new version 4 is that there really has not been much thought into N-tier environments. It still got a feel about it being a 2 tier solution with a lot of boiler plate code still needed to be done by the end user (developer), to get it working in a robust and dependable N-Tier way.
So far I did not like EF. Although I liked the tools and how easy it was to create certain types of mappings and relations, Other types were a pain and the Linq support in EF wasn't so great (couln't create my own filter extension methods).
Is the new EF in .Net 4.0 better. Given what I have stated so far is there a chance I will like it.
The reson I ask this is because I use linq2sql a lot and do not like the feeling that the platform I am using is about to go obsolete. I would like to upgrade to something that is as similar as possible to what I already have.
Thanks for your opinions
It's only an opinion, but I believe that the new EF will be much improved. They will almost certainly have some kind of migration path from Linq to SQL. Whether it will look like Linq to SQL is another story. The two tools have somewhat different philosophies.
While EF will be designed for enterprise scenarios, it is my hope that the next version will still be lightweight enough to serve as an adequate replacement for L2S in small application scenarios.
I am really optimistic about EF 4.0 from all that I have seen thus far. The beta release is already available to MSDN subscribers and it addresses a lot of the concerns around POCO, Persistence Ignorance, N-Tier support and all that. I continue to recommend reading the ADO.NET team blog as a great resource for what's changed.
You can't compare it to the first release because this is a very big overhaul and a lot has changed.
That said, initial adopters always get the worst of it because they are the first to run into bugs and new problems while the late comes can benefit from the lessons learnt by the early adopters.
There has been a lot of improvements. I have ran in to a couple of strange issues but nothing unsolvable yet. It took me a few hours to understand how POCO works meaning they spent a lot of. I recommend you download VS2010 and play around with it yourself!
Have a look at this presentation, and you will know why EF worth your time.
How to Think Like the Entity Framework Presentation: http://blogs.teamb.com/craigstuntz/2009/09/11/38394/
I was listening to a podcast recently that was discussing at length the short comings of Entity Framework (EF).
But, their opinions may need to be taken with a grain of salt (by me), as from what I could gather:
These were folks that were ORM experts.
They either made their living off of ORM tools, or their hobby
They were using ORM tools for large scale applications
They were also very concerned with the uber-tactics of ALT.NET that I'm not necessarily concerned with (YET)
My overall question is:
For what type of project is Entity Framework currently suited?
But here are a few sub-questions that may help you get where I'm headed with that question:
Is EF better than nothing? I'm tired of doing everything by hand.
Does it come close to "solving the same problem" as LINQ to SQL? 2a. If yes, when would one be suited over the other? * found a thread on this question as I was going over questions with this tag, so nevermind *
Does it lend itself to simple 'quick and dirty' applications, such as when the bulk of your administrative CRUD forms?
edit: for those that might be curious, I am mostly working on small to medium sized applications. That can guide your response, or not.
The Entity Framework is suitable for all applications which would benefit from having an ORM layer. Daniel Simmons post goes into detail on this.
http://blogs.msdn.com/dsimmons/archive/2008/05/17/why-use-the-entity-framework.aspx
Entity Framework is similar in many ways to Linq for SQL but is not tied to MS SQL Server which Linq for SQL is. In addition EF supports more flexible mapping between your business/domain objects and the data tables. Linq for SQL supports more of a one to one mapping whereas EF supports ability to map a single object to multiple tables, or a single table to multiple objects. You do have decent designer support in both.
In the open source world, NHibernate is probably the most advanced and in many ways is the more mature product (it certainly supports a wider array of features to some regard). But with EF you get the full support of MS and the close integration into the visual studio toolset and .net framework stack. EF also as a better Linq profider than NH at the time of writing.
For a quick and dirty application i would lean towards Linq for SQL to be honest, if you can live with MS SQL Server and the mapping restrictions.
For a more complex application i would use EF or NHibernate.
You might be interested in a vote of confidence post i gave on the EF
http://blog.keithpatton.com/2008/06/24/A+Vote+Of+Confidence+For+The+Entity+Framework.aspx