I am going to work with Linq data access model. Which Model performance is better? and why to use and why not to use Linq.
Thanks
There is always a trade off between abstraction level and performance, so of course, Linq To Entities or Linq To Sql, which both work on top of ADO.NET, will be slower than ADO.NET.
It is all about what level of performance you need for your particular project. If performance is more crucial for you than ease of development then go with straight DataReaders. If not then go for Linq To Entities.
Linq to SQL and Entity Framework etc. all use ADO.NET internally, thus they are slower since they do more work than ADO.NET alone.
The idea is not to get the best performance but the best abstraction, model your domain with objects so you can reason about your data and the commands that operate on that data.
So it's a good idea to trade some performance for other aspects.
Related
I need a help on the database access in 3-tier architecture. I am developing application in asp.net and linq. In database there are at least 9 master tables and total of 22 tables. For managing data I need to use a view for each master table.
My question is what is more convenient on runtime or for faster execution?
To use page level queries (using multiple joins having at least 5-6 tables) in DataAccessLayer using linq
To use view and refer them in DataAccessLayer
Adding all queries to a stored procedure and then bind them all.
Which one is best practice? Is views makes page heavy while runtime?
Linq2SQL queries generally wind up as parameterized queries on your database.
There are many discussions on SO comparing the difference in performance like Are Stored Procedures more efficient, in general, than inline statements on modern RDBMS's? and Stored Procedures vs Parameterized Queries
I believe the concensus is that the benefit of the flexibility that an ORM like Linq2SQL gives generally outweighs any perceived performance loss.
IMO, LINQ2SQL will do 90% of the job just fine for most of your data access requirements, and if you have any special needs where a PROC makes more sense (e.g. a really data intensive or batch transaction), you can write one or two procs and these to your DataContext.
However, while we are at it, I wouldn't consider Linq2SQL on a new project. Why not look at Entity Framework 4+? (OP is using .NET 3.5)
Edit
If your table Foreign keys are set up correctly, when you drag your underlying tables into your Linq DBML's, you will find that you hardly ever need to join 'manually' as the ORM will handle the underlying navigation for you.
e.g.
var myUpvotes = Users.Where(u => v.UserId == someUser)
.Votes.Where(v => v.Upvote == true)
.Count();
One concept you will need is Eager vs Lazy loading. This will definitely impact the performance of your 'joins'
I think best practice would be your #1, but you must keep an open-mind about bringing #2 or #3 to bear on the problem if the performance needs demand it. In other words, run with #1 as far as you can, but be willing to use #2 or #3 to improve those parts of the code only if/when you need it.
I've found (and agree with #nonnb) that the productivity improvement and flexibility of using Linq2SQL / ORMs makes it the right choice most of the time, but there are a few times when you need to be willing to make use of a strategic SP in your overall plan - its not an either/or decision; use both as necessary. Generally SP's will be faster, but most of the time not enough to make a difference in your application - but they should be kept in your toolset because in the right scenarios, they can make HUGE improvements when they are really needed.
Is it a bad idea to use linq to sql as my data-layer to retrieve data, and then populate the data into my business layer?
Am i going to be facing performance problems?
What is the most efficient way of getting data from database and populating it into my business objects?
Linq to Sql will give you good enough performance for all but the most demanding applications. If you are only ever considering using a SQL Server database, Linq to SQL is a very productive ORM to work with, and it "just works".
I used to use Linq to SQL on all .NET apps I developed on SQL Server. Then I discovered the simplicity and elegance of Entity Framework (4.1) and the Code First approach. This approach works nicely with Domain Driven Design, while allowing you to write business objects without writing any persistance code at all, by means of a convention based approach. Worth thinking about.
If you don't do anything stupid LINQ2SQL won't give you big performance problems. There is a small overhead using LINQ2SQL but that is quite small.
The most efficient way would be to select straight into your business objects in the select part.
var myResult = from product in context.Products
where product.StockQty > 10
select new MyBusinessProduct
{
Name = product.Name,
Category = product.Category,
etc = product.etc, //...
}
Often you can use your LINQ-objects as your business objects, you can decorate them with your business methods in a partial class and also implement the partial methods on the LINQ classes to implement validation rules.
I want to create a web application using ASP.NET. Which method should I use, LINQ or SQL query? Which gives the best performance? Please help me.
This is an excellent series by a CLR Performance Architect describing LINQ to SQL performance: http://blogs.msdn.com/b/ricom/archive/2007/06/22/dlinq-linq-to-sql-performance-part-1.aspx
Performance-wise I think you'll always be better off with SQL. If you take a look at the generated SQL code which LINQ produces you'll notice that it's not always that top notch.
On the other hand, LINQ isn't slow. It's not as fast as SQL, but it's definitely not slow. If you think about the advantages LINQ provides I would always prefer LINQ over SQL if I have the choice.
If performance is the BIG issue tho, sticking with SQL might be your best shot. If you were just wondering if the difference was that major, and if you don't expect database-performance to be a bottleneck I'd go for LINQ.
I am working on architecture of mid sized web application & for my DAL layer i am having 3 options
1) Traditional Stored proc Based Architecture (Using NTiers Template of Codesmith)
2) LINQ To SQL (or PLINQO Template of codesmith)
3) LINQ To Entity
From above LINQ to Entity is out of reach as we need to start application very quickly and we don't have the sufficient skillset for the same and as team has never worked on any OR/M tools it will be steep learning curve for them (This is what i read some where)
I prefer to go ahead with LINQ to SQL (But only fear is microsoft is not going to support or enhance LINQ to SQL further), from my point of view if microsoft is not going to enhance it further i am not having any issue as whatever feature i require in my project it is sufficient.
Now my issue is should i use linq to sql or should i stick to traditional architecture ?
OR else any other option is there ...
EDIT : I am going to use SQL Server as database and it does not require to interact with any other database
One of the most important objective in designing DAL Layer is faster development and maintainability for future database table changes, as there are chances that field may increase or decrease in future.
Also if you feel that any ORM tool is really good and does not have steep learning curve then also we can use
Please provide suggestions
As you are working in medium size project, I would suggest you to use LINQ-TO-SQL because of these advantages
Advantages using LINQ to SQL:
•No magic strings, like you have in SQL queries
•Intellisense
•Compile check when database changes
•Faster development
•Unit of work pattern (context)
•Auto-generated domain objects that are usable small projects
•Lazy loading.
•Learning to write linq queries/lambdas is a must learn for .NET developers.
Regarding performance:
•Most likely the performance is not going to be a problem in most solutions. To pre-optimize is an anti-pattern. If you later see that some areas of the application are to slow, you can analyze these parts, and in some cases even swap some linq queries with stored procedures or ADO.NET.
•In many cases the lazy loading feature can speed up performance, or at least simplify the code a lot.
Regarding debuging:
•In my opinion debuging Linq2Sql is much easier than both stored procedures and ADO.NET. I recommend that you take a look at Linq2Sql Debug Visualizer, which enables you to see the query, and even trigger an execute to see the result when debugging.
•You can also configure the context to write all sql queries to the console window, more information here
Regarding another layer:
•Linq2Sql can be seen as another layer, but it is a purely data access layer. Stored procedures is also another layer of code, and I have seen many cases where part of the business logic has been implemented into stored procedures. This is much worse in my opinion because you are then splitting the business layer into two places, and it will be harder for developers to get a clear view of the business domain.
There is no absolutely preffered way of writing DAL. These are all options. Which one to choose depends on your project, your skills and your inclinations.
Normally, with LINQ you can expect to be more productive. On the other hand, the DAL built with stored procedures can be expected to perform faster.
The issue only comes when you need some specific queries that the default LINQ to SQL provider won't be able to generate to be blazingly fast. In that case you will have to tap into your LINQ code to plug in your custom stored procedures where needed.
Regarding LINQ to SQL support and further development, it was grounded a long time ago already. So no official further development. Note: that is true for LINQ to SQL (it will be taken over by EF) relational solution, not for the main LINQ functionality.
Entity Framework in its v.1 only received massive critics. You're advised to wait until v2 comes out.
The most important limitation with LINQ (over Entity Framework or any other popular ORM) is that it doesn't support 1 to n mappings. That is, each your LINQ class can only map to a single table, not represent some sort of view over several others. Maybe it's not important to you, but maybe it is. Depends on your project.
The argument of stored procedures vs ORM's is long-standing and unlikely to be resolved any time soon. My recommendation would be to go with an ORM (Linq-to-Sql in your case).
Yes, stored procedures will always be faster since the queries are precompiled. The real question you have to ask yourself is whether you have such a performance-intensive system that your users will actually notice the difference. Keep in mind that using stored procedures means that you will need to manually write all your own queries where using an ORM does this for you. This usually means that an ORM will speed up your development.
Since you mention that speeding up development time is one of your goals I would recommend Linq-to-Sql - otherwise you will basically write the entire DAL yourself.
All of the options you've provided have significant drawbacks. None of them meet the requirements you've set out.
You need to prioritize what is most important for you.
If learning curve is your biggest issue, stay away from all ORMs if you are already comfortable with ADO.NET, DataTables, etc.
If development speed is your biggest issue, you should learn an ORM and go that route. The easiest ORM to recommend is NHibernate. Every other ORM has significant weaknesses. NHibernate works in the vast majority of projects, whereas other ORMs are much more situationally appropriate (depending on your DB design, model design, agility requirements, legacy schema support, etc.). All ORMs have learning curves, they just come into play at different times and in different ways.
Just to expand on #Developer Art, using the traditional stored proc approach enables you to put business logic in the database. Usually you will want to avoid this, but sometimes it is necessary to do. Not to mention you could also enforce constraints and permissions at the database level using this approach. It all depends on your requirements.
With the limitations mention I would say just stick to adhoc/custom queries and ADO.NET and not go for any jazzy stuff. Also stored procedure based DAL are faster is a notion based lame arguments like stored procedures are precompiled but they are not. All that they have is query plan cache. So lesser the investment in stored procedures the better you are. My advice ADO.Net and custom dynamic queries constructed from entity objects.
I have an existing web app that has a data layer and a bll that calls the data layer. The data layer is ado.net that calls stored procedures.
I created another project in vs.net for linq-to-sql, dragged all my tables over.
Would it be wise to just start using linq or should I spend the time and re-write all the db logic in linq just so I don't have any issues having 2 data layers!
If it ain't broken, don't fix it.
Why would you want to rewrite completely your perfectly working data layer? ADO.NET + stored procedures is a great choice. Keep it. At the same time you can start playing with LINQ.
Anyway, you will need some practice with LINQ to see what it can and what it cannot do before you will be able to decide on the new data layer architecture. There are some situations that LINQ cannot handle right out of the box, so you will need to use tricks or substitute default implementation with your own queries. At the end of the day you may have decided, it was not worth it.
My suggestion is to gain some experience with it separately and not start rewriting everything completely just because LINQ is cool.
Unless your current data layer is broken for some reason, don't just start implementing a new one, just because you can.
Although if currently the datalayer consists of using stored procedures and that becomes cumbersome to maintain, switching to L2S (or any other OR/M for that matter) might be a valid reason. Just don't think it'll be only a matter of dragging some columns to a canvas and be done. Dependent if there's any logic in the sprocs, the logic has to exist somewhere...
I'd say until you can justify the costs of switching your datalayer entirly, stick with your current implementation.
Please be clear: there is a major difference between Linq and LinqToSql. Linq is great and you should be using it if at all possible. LinqToSql is not great and has many problems:
Do not use the Visual Studio 2008 LinqToSql O/R Designer
The drawbacks of adopting Linq To Sql
To use Linq, you need an ORM of some sort. You have many options for ORMs in the .NET world. If you like what LinqToSql offers, you may be most comfortable using SubSonic. In the long run, NHibernate is the best choice for a .NET ORM right now. I wrote a lot more on choosing a .NET ORM here:
.NET and ORM - Decisions, decisions
In the end, there is no reason you can't have two or more different data layer technologies in the same application. There are good reasons not to do this however and so it should be avoided if at all possible.
Also, here's a compelling write-up against using stored procedures:
Stored procedures are bad, m'kay?