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Harvesting some LINQ links

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This post summarizes some things we've noted in tracking the reaction to XLinq in the press and blogosphere, and points to some resources we've discovered along the way.

One thing we've noted in the LINQ forum and elsewhere is that people seem to think that LINQ == DLinq, i.e. that LINQ is just some C# syntax for embedded SQL.   As we see it, however, LINQ provides a model of data access that unifies query and transformation across an extensible set of domains, including .NET collections , XML data, relational data, ADO.NET datasets, and more in the future.  Other development environments (e.g. Java) support different languages and APIs for different types of data:  JDBC for relational data, XQJ for XML databases, Groovy for XML text, and so on. With LINQ, developers use a common set of language features to query and manipulate  XML, relational data (in a DBMS or in a cache), and objects. 

It's not so much a different syntax for embedded SQL as bringing a common set of query operators to all types of data that can support the IEnumerable<T> abstraction.  It may be asking a bit much to expect the relational purists to give LINQ a fair hearing, but in reality it is doing much of what they have long advocated - making it more feasible to work with data via something very much like and very much inspired by the relational algebra.  See for example Ted Neward's piece on LINQ and similar approaches. 

One particularly powerful area of synergy between the LINQ approach and the relational algebra is exemplified by the new LINQ join operators. Anders' talk with Jon Udell focuses on this new feature in the May CTP, and many of the examples show how to use various types of join operations to simplify common XML processing tasks.  People who have seen the podcast seem to agree: "Wow!".  This isn't PowerPoint ware, this is an hour of hands-on coding and explanation by LINQ/XLinq's principal designer.

Paul Kinlan asks if XLinq has an efficient way to process very large documents without loading them into memory first.  The short answer is "no, but we're thinking about this." It would be very good to hear from others about what their needs are, what kinds of XML data they are processing, why they don't use an XML-enabled DBMS such as SQL Server 2005 to do the heavy lifting, etc.

Finally, we came across an interesting blog by Kevin Hoffman that has a number of posts on LINQ topics.  My favorite so far is his explanation of lambda expressions and expression trees, a topic I have been trying to get up the courage to tackle my series on XLinq design issues in my own blog.

Be sure to let us know about any XLinq-related sites that you find interesting or useful, and feel free to contact us either via the Contacts link or the comments section if you have questions or problems applying XLinq to real XML problems.

Mike Champion

Comments

  • Anonymous
    June 05, 2006
    trackback - http://devauthority.com/blogs/jwooley/archive/2006/06/05/1222.aspx
  • Anonymous
    June 05, 2006
    My question is
    how will Linq perform in critical three tiers applications?

    And how can the queries be controlled to get the best performance?

    Can the template used for SQLMetal be changed to get other code output?
  • Anonymous
    June 06, 2006
    I think this is more of a DLinq question than an XLinq question but I'll try.  LINQ doesn't impose a particular design pattern, e.g the way RoR imposes MVC.  There will be LINQ-enabled APIs on the client that abstract away the mid-tier, LINQ over ADO.NET DataSets, more LINQ over ADO.NET stuff that we'll be talking more about at TechEd, and so on.  XLinq can be used on the client (including mobile Compact Framework clients), the mid-tier, and (I hope) in SQL Server .NET stored procedures.
    So, LINQ is a common programming model for data, not a model for data processing.  

    I'm not too sure about how to optimize DLinq queries for performance.  In LINQ and XLinq, some things such as in-memory joins will be more efficient than a simple hand-rolled implementation, but not as efficient as database join performed by an optimized query over a well-indexed DB. There's no magic in at least this release of the LINQ stuff, and people will be figuring out how to tune LINQ queries for fun and profit.

    I don't know whether SQLMetal templates can be modified in the way you suggest.  Try the LINQ forum http://forums.microsoft.com/MSDN/ShowForum.aspx?ForumID=123&SiteID=1
  • Anonymous
    June 07, 2006
    One more link you could find interesting: http://linqinaction.net is a site dedicated to LINQ, XLINQ and DLINQ.
  • Anonymous
    June 12, 2006
    Sam Druker (my boss's boss's boss, on the left) and Anders Hejlsberg talk about the May CTP of LINQ,...
  • Anonymous
    June 12, 2006
    The comment has been removed
  • Anonymous
    June 21, 2006
    In case you missed it, Somasegar (Microsoft's VP of Developer Division) blogged today about some of the...
  • Anonymous
    June 16, 2009
    PingBack from http://fixmycrediteasily.info/story.php?id=7440