Using EF4 how can I track the # of times a record is part of a Skip().Take() result set

So using EF4, I'm running a search query that ends with this common function:

query = query.Skip(5).Take(10);

Those records in the database have a column called ImpressionCount, which I intend to use to count the number of times that each record displayed on a page of search results.

What's the most efficient way to do this? Off the top of my head, I'm just going to look at the result set, get a list of ID's and then hit the database again using ADO.NET to do something like:

UPDATE TableName SET ImpressionCount = ImpressionCount + 1 WHERE Id IN (1,2,3,4,5,6,7,8,9,10)

Seems simple enough, just wondering if there's a more .NET 4 / Linq-ish way to do this that I'm not thinking of. One that doesn't 开发者_如何学JAVAinvolve another hit to the database would be nice too. :)

EDIT: So I'm leaning towards IAbstract's response as the answer since it doesn't appear there's a "built in" way to do this. I didn't think there was but it never hurts to ask. However, the only other question I think I want to throw out there is: is it possible to write a SQL trigger that could only operate on this particular query? I don't want ImpressionCount to update on EVERY select statement for the record (for example, when someone goes to view the detail page, that's not an impression -- if an admin edits the record in the back end, that's not an impression)...possible using LINQ or no?

SQL Server would somehow need to be able to identify that the query was generated by that Linq command, not sure if that's possible or not. This site is expecting relatively heavy traffic so I'm just trying to optimize where possible, but if it's overkill, I might just go ahead and hit the database again one time for each page of results.

In my opinion, it is better to go ahead and run with the SQL command as you have it. Just because we have LINQ does not mean it is always the best choice. Your statement gives you a one-call process to update impression counts and should be fairly quick.

You can technically use a .Select to modify each element in a returned result, but it's not idiomatic C#/linq, so you're better off using a foreach loop.

Example:

var query = query.ToList().Select(x => { x.ImpressionCount++; return x; });

As IAbstract said, be careful of performance issues. Using the example above, or a foreach will execute 10 updates. Your one update statement is better.

I know Linq2NHibernate has this same issue - trying to stick with Linq just isn't any good for updates (that's why it's called "language integrated query");

Edit:

Actually there's probably no reason why EF4 or NHibernate couldn't parse the select expression, realize it's an update, and translate it into an update statement an execute it, but certainly neither framework will do that. If that were something that could happen, you'd want a new .Update() extension method for IQueryable<T> to explicitly state that you're modifying data. Using .Select() for it is a dirty hack.

... which means there's no reason you couldn't write your own .Update(x => x.ImpressionCount++) extension method for IQueryable<T> that output the SQL you want and call ExecuteStoreCommand, but it would be a lot of work.