Is LINQ to SQL deprecated?_问答_开发者_运维开发者技术经验分享

Back in late 2008 there was a lot of debate about the future of LINQ to SQL. Many suggested that Microsoft's investments in the Entity Framework in .NET 4.0 were a sign that LINQ to SQL had no future. I figured I'd wait before making my own decision since folks were not in agreement.

Fast-forward 18 months and I've got vendors providing solutions that rely on LINQ to SQL and I have personally given it a try and really enjoyed working with it. I figured it was here to stay.

But I'm reading a new book (C# 4.0 How-To by Ben Watson) and in chapter 21 (LINQ), he suggests that it "has been more or less deprecated by Microsoft" 开发者_如何学运维and suggests using LINQ to Entity Framework.

My question to you is whether or not LINQ to SQL is officially deprecated and/or if authoritative entities (Microsoft, Scott Gu, etc.) officially suggest using LINQ to Entities instead of LINQ to SQL.

For all the "Linq-to-SQL is dead" folks: Scott Guthrie himself clearly mentioned at TechEd Europe that Linq-to-SQL is FULLY SUPPORTED in .NET 4, and Damien Guard posted a blog post on what changes and improvements have been made for Linq-to-SQL in .NET 4.

To quote Mark Twain: "Reports of my death have been greatly exaggerated"......

Last I checked, this very site uses (or used to use) Linq To SQL. Joel Spolsky mentions this in his GoogleTechTalk: http://www.youtube.com/watch?v=NWHfY_lvKIQ.

When speaking of software, "dead" is a figurative modifier (software doesn't die in any literal, biological sense), so this debate can linger on as long as the involved parties refuse to define in any literal sense what it means for "Linq To Die". Or, LTD for short. Hence, as of this moment, the LTD debate has lingered for two years. All because of a little linguistic ambiguity.

Those who say that "L2S is dead" are generally referring to the fact that L2S isn't going to receive too many (if any) new features. Updates to Linq (like the updates mentioned in Damien Guard's post) are likely to be confined to performance, usability, and stability updates. Of course, some developers might actually argue that this is a good thing (probably the same developers who are a wee bit angry about the new dynamic type).

Those who say that "L2S is not dead" are generally referring to the fact that L2S isn't going to be cut altogether from .Net (at least not anytime soon). Think: ADO. It may lose some of its traction amongst practicing developers (and that may be the unspoken desire of those crafty folks at Microsoft), but that doesn't mean that you won't be able to use L2S if you want to. It just means that Microsoft isn't trying to tantalize the masses with it.

When starting a project, I actually think it's great that I have a choice between EF and L2S. As Bill Wagner ~~points out~~, there's a time and a place for both.

I am late to this discussion, but I wanted to point out that as far back as 2008, the Link to SQL Project Manager (Tim Mallalieu) made this announcement in his blog post,

"As of .NET 4.0, LINQ to Entities [rather than LINQ to SQL] will be the recommended data access solution for LINQ to relational scenarios."

I have found no other more recent announcements to the contrary.

No it is not. The team are still working on improving it.

Make sure to have a look at this article posted on InfoQ.com - it's a really interesting one. Its conclusion: "[O]ver the long run LINQ to SQL and LINQ to Entities will merge. In the mean time, development work on LINQ to SQL will not end entirely."

LINQ to SQL tools in Visual Studio

LINQ to SQL was the first object-relational mapping technology released by Microsoft. It works well in basic scenarios and continues to be supported in Visual Studio, but it's no longer under active development. Use LINQ to SQL when maintaining a legacy application that's already using it, or in simple applications that use SQL Server and do not require multi-table mapping. In general, new applications should use the Entity Framework when an object-relational mapper layer is required.

i guess it's inevitsble that they'll merge. EF is really an enterprise level implementation of LINQ over db objects. linq2sql was to all intents a proof of concept(and a lot more) that actually grew legs but fuelled many of the ideas that we now see in EF. at the end of the day, the DAL layer (nhibernate, EF, l2s, subsonic etc) should be pretty far down the chain so as to negate any differences in the client BO code that implents the LINQ service - hot swappable would be the end game via DI.