>>>>>>>I'm trying to retrieve an application from my database. I have a Data Context in my app called AppSecurityDataDataContext. Here's my query:
>>>>>>>
>>>>>>>

>>>>>>>{ 
>>>>>>>    AppSecurityDataDataContext dc = new AppSecurityDataDataContext();
>>>>>>>    var app = from a in dc._Applications
>>>>>>>                where a.ApplicationId = ApplicationID
>>>>>>>                select a;
>>>>>>>
>>>>>>>}
>>>>>>>

>>>>>>>
>>>>>>>I'm getting "Could not find an implementation of the query pattern for source type 'System.Data.Linq.Table<AppSecurity._Application>'. 'Select' not found. Are you missing a reference to 'System.Core.dll' or a using directive for 'System.Linq'?"
>>>>>>>
>>>>>>>I have the using statement in my class. This other method works:
>>>>>>>
>>>>>>>

>>>>>>>public static void AddApplication(Application Application)
>>>>>>>{
>>>>>>>    _Application app = new _Application
>>>>>>>    {
>>>>>>>        ApplicationName = Application.ApplicationName
>>>>>>>    };
>>>>>>>
>>>>>>>    _DataContext._Applications.InsertOnSubmit(app);
>>>>>>>
>>>>>>>    try
>>>>>>>    {
>>>>>>>        _DataContext.SubmitChanges();
>>>>>>>    }
>>>>>>>    catch (Exception e)
>>>>>>>    { 
>>>>>>>    }
>>>>>>>}
>>>>>>>

>>>>>>>
>>>>>>>Anyone see what's wrong here?
>>>>>>
>>>>>>==
>>>>>
>>>>>umm, huh? What does "==" mean?
>>>>Not the same as "=":

where a.ApplicationId = ApplicationID

>>>
>>>If I remove the Where clause, the comp error still occurs
>>
>>Then it looks as if it indeed isn't able to reference the System.Linq namespace (Your second example isn't using Linq). Are you sure you have a reference to the System.Core.dll in the project?
>
>
>My bad. I was using System.Data.Linq, not System.Linq. Not it works.
>
>So that begs the question: What the difference between the two?

I'm guessing System.Data.Linq is for Linq to DataSets.