Bill Morefield My thoughts, discoveries, and occasional rambiings.

July 6, 2009

Let Me Tell You About This Little Thing Called the Internet

Filed under: blog — Bill Morefield @ 8:30 pm

I find it amazing that in 2009 there are still so many businesses that do not have even the most basic of web sites.  I tried to look up a couple of restaurants in Morristown, TN today.  One did have a MySpace page that I found after playing a few rounds of the “pick the right search terms” game, but the other had absolutely nothing that I was able to find except for review on third part sites.


I imagine that anyone reading this probably already know this, but a simple one page web site with your hours, contact info, and some basic information (menu for a restaurant, etc.) will cost you less than $10 a month.  That’s probably the cheapest advertising you’ll ever get and I think you’ll find it worth every penny.

July 2, 2009

IN Queries using Linq to SQL

Filed under: Uncategorized — Bill Morefield @ 12:30 am

    I’ve been working on my first “real” project using Linq to SQL for the last few nights.  So far I’ve been quite happy, but tonight I ran into my first real “how do I do this?” moment.


    Simplifying the description a little, I have three types of objects.  One is a location, the second is a person, and the third we’ll call an object.  An object is assigned to a location.  Right now a person is assigned to a location, but may be assigned to more than one location.  What I need to find out is which objects are at a location or locations that a person is assigned to.


    That to me in would be something like this as a SQL query:

    SELECT FROM Objects WHERE Objects.location IN (SELECT PersonAssignments.location FROM PersonAssignments WHERE PersonAssignments.person = @PERSONID)


    In my experience ‘IN’ queries tend to be where most simple ORM systems break down.  Usually the only options I’ve found are to either write a stored procedure in SQL or come up with some hack that looks even worse than it performs.  So I began skimming through documentation and then searching and came across an article by Rob Conry at


    In short, it can be done, but you have to think about the problem a little differently.  First we get the locations where the person is assigned.


    MyDB db = new MyDB();


    var locationList = from assignment in db.PersonAssignments

    where assignment.location == personId

    select assignment;


    And now we can then write our query like this:

    var objectList = from object in db.Objects

    where locationList.Contains(object.location)



    It seems a little backwards to me at first, but works.  A nice feature (see the blog post above for a more details explination) is that since a query is only executed when you enumerate the results, this generates a single query when you enumerate the objectList.  Also nice is that you can do the NOT IN query the same way by simply using a not (!) opeator on the conditional.  So to get all the objects not in a location assigned to a person we can do:

    var objectList = from object in db.Objects

    where !locationList.Contains(object.location)





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