Entity Framework VS LINQ to SQL VS ADO.NET with stored procedures? [closed]_问答_开发者

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How would you rate each of them in terms of:

Performance
Speed of development
Neat, intuitive, maintainable code
Flexibility
Overall

I like my SQL and so have always been a die-hard fan of ADO.NET and stored procedures but I recently had a play with Linq to SQL and was blown away by how quickly I was writing out my DataAccess layer and have decided to spend some time really understanding either Linq to SQL or EF... or neither?

I just want to check, that there isn't a great flaw in any of these technologies that would render my research time useless. E.g. performance is terrible, it's cool for simple apps but can only take you so far.

Update: Can you concentrate on EF VS L2S VS SPs rather than ORM VS SPs. I'm mainly interested by EF VS L2S. But am keen to have them compared against stored procs too since plain SQl is something I know a lot about.

First off, if you're starting a new project, go with Entity Framework ("EF") - it now generates much better SQL (more like Linq to SQL does) and is easier to maintain and more powerful than Linq to SQL ("L2S"). As of the release of .NET 4.0, I consider Linq to SQL to be an obsolete technology. MS has been very open about not continuing L2S development further.

1) Performance

This is tricky to answer. For most single-entity operations (CRUD) you will find just about equivalent performance with all three technologies. You do have to know how EF and Linq to SQL work in order to use them to their fullest. For high-volume operations like polling queries, you may want to have EF/L2S "compile" your entity query such that the framework doesn't have to constantly regenerate the SQL, or you can run into scalability issues. (see edits)

For bulk updates where you're updating massive amounts of data, raw SQL or a stored procedure will always perform better than an ORM solution because you don't have to marshal the data over the wire to the ORM to perform updates.

2) Speed of Development

In most scenarios, EF will blow away naked SQL/stored procs when it comes to speed of development. The EF designer can update your model from your database as it changes (upon request), so you don't run into synchronization issues between your object code and your database code. The only time I would not consider using an ORM is when you're doing a reporting/dashboard type application where you aren't doing any updating, or when you're creating an application just to do raw data maintenance operations on a database.

3) Neat/Maintainable code

Hands down, EF beats SQL/sprocs. Because your relationships are modeled, joins in your code are relatively infrequent. The relationships of the entities are almost self-evident to the reader for most queries. Nothing is worse than having to go from tier to tier debugging or through multiple SQL/middle tier in order to understand what's actually happening to your data. EF brings your data model into your code in a very powerful way.

4) Flexibility

Stored procs and raw SQL are more "flexible". You can leverage sprocs and SQL to generate faster queries for the odd specific case, and you can leverage native DB functionality easier than you can with and ORM.

5) Overall

Don't get caught up in the false dichotomy of choosing an ORM vs using stored procedures. You can use both in the same application, and you probably should. Big bulk operations should go in stored procedures or SQL (which can actually be called by the EF), and EF should be used for your CRUD operations and most of your middle-tier's needs. Perhaps you'd choose to use SQL for writing your reports. I guess the moral of the story is the same as it's always been. Use the right tool for the job. But the skinny of it is, EF is very good nowadays (as of .NET 4.0). Spend some real time reading and understanding it in depth and you can create some amazing, high-performance apps with ease.

EDIT: EF 5 simplifies this part a bit with auto-compiled LINQ Queries, but for real high volume stuff, you'll definitely need to test and analyze what fits best for you in the real world.

Stored procedures:

(+)

Great flexibility
Full control over SQL
The highest performance available

(-)

Requires knowledge of SQL
Stored procedures are out of source control
Substantial amount of "repeating yourself" while specifying the same table and field names. The high chance of breaking the application after renaming a DB entity and missing some references to it somewhere.
Slow development

ORM:

(+)

Rapid development
Data access code now under source control
You're isolated from changes in DB. If that happens you only need to update your model/mappings in one place.

(-)

Performance may be worse
No or little control over SQL the ORM produces (could be inefficient or worse buggy). Might need to intervene and replace it with custom stored procedures. That will render your code messy (some LINQ in code, some SQL in code and/or in the DB out of source control).
As any abstraction can produce "high-level" developers having no idea how it works under the hood

The general tradeoff is between having a great flexibility and losing lots of time vs. being restricted in what you can do but having it done very quickly.

There is no general answer to this question. It's a matter of holy wars. Also depends on a project at hand and your needs. Pick up what works best for you.

your question is basically O/RM's vs hand writing SQL

Using an ORM or plain SQL?

Take a look at some of the other O/RM solutions out there, L2S isn't the only one (NHibernate, ActiveRecord)

http://en.wikipedia.org/wiki/List_of_object-relational_mapping_software

to address the specific questions:

Depends on the quality of the O/RM solution, L2S is pretty good at generating SQL
This is normally much faster using an O/RM once you grok the process
Code is also usually much neater and more maintainable
Straight SQL will of course get you more flexibility, but most O/RM's can do all but the most complicated queries
Overall I would suggest going with an O/RM, the flexibility loss is negligable

LINQ-to-SQL is a remarkable piece of technology that is very simple to use, and by and large generates very good queries to the back end. LINQ-to-EF was slated to supplant it, but historically has been extremely clunky to use and generated far inferior SQL. I don't know the current state of affairs, but Microsoft promised to migrate all the goodness of L2S into L2EF, so maybe it's all better now.

Personally, I have a passionate dislike of ORM tools (see my diatribe here for the details), and so I see no reason to favour L2EF, since L2S gives me all I ever expect to need from a data access layer. In fact, I even think that L2S features such as hand-crafted mappings and inheritance modeling add completely unnecessary complexity. But that's just me. ;-)

There is a whole new approach that you may want to consider if what you're after is the power and performance of stored procedures, and the rapid development that tools like Entity Framework provide.

I've taken SQL+ for a test drive on a small project, and it is really something special. You basically add what amounts to comments to your SQL routines, and those comments provide instructions to a code generator, which then builds a really nice object oriented class library based on the actual SQL routine. Kind of like entity framework in reverse.

Input parameters become part of an input object, output parameters and result sets become part of an output object, and a service component provides the method calls.

If you want to use stored procedures, but still want rapid development, you might want to have a look at this stuff.