Still celebrating National IT Professionals Day with 3 months of free Premium Membership. Use Code ITDAY17

x
?
Solved

"Limit" in entity framework?

Posted on 2010-09-20
10
Medium Priority
?
2,158 Views
Last Modified: 2013-11-11
Hi!

How can I with entity framework, do some "limit" request, e.g. in my case, I want to return the 3 last object.

So, how to do this on an IQueryable object?

Thank you!
0
Comment
Question by:Nargzul
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 5
  • 3
  • 2
10 Comments
 
LVL 53

Expert Comment

by:Dhaest
ID: 33715474
Do you mean something like the skip() and take() methods ?

http://www.vikramlakhotia.com/Using_Take_and_Skip_method_in_LINQ_queries.aspx
0
 
LVL 1

Author Comment

by:Nargzul
ID: 33715524
Not exactly, because, if we have something like this:
Skip(x).Take(y)

I only want to specify the Y.

I know I can OrderByDescending, Take and after this OrderBy, but this will make two sort instead of one, it's costly
0
 
LVL 53

Expert Comment

by:Dhaest
ID: 33715579
I'm afraid that there will be no other way, then to reverser the result (like you already did) to get the records.

I'm not sure, but maybe you can use the elementAt(...)

Something like this:

Dim newaccount = From n In db.accounts.ElementAt(db.accounts.Count() - 3).Take(3)
0
VIDEO: THE CONCERTO CLOUD FOR HEALTHCARE

Modern healthcare requires a modern cloud. View this brief video to understand how the Concerto Cloud for Healthcare can help your organization.

 
LVL 1

Author Comment

by:Nargzul
ID: 33715607
I don't think, because ElementAt return my object type and no more an IQueryable object.

It should be possible to do something like

From n In db.accounts.Skip(db.accounts.Count() - 3).Take(3), but I'm almost sure it will load the full collection.
0
 
LVL 53

Expert Comment

by:Dhaest
ID: 33715675
>> I'm almost sure it will load the full collection.

I'm afraid so ..
0
 
LVL 1

Author Comment

by:Nargzul
ID: 33715759
So have you an idea to avoid that? The table will contains a lot of data, and even if the table will be cleaned regularly, it will not be enough. because this will be called on every page of my remote application
0
 
LVL 64

Expert Comment

by:Fernando Soto
ID: 33716793
Hi Nargzu;

First get a count of the records and then use a Skip( count - 3 ). For example using the Adventureworks DB as the source the following will work.

DataClasses1DataContext db = new DataClasses1DataContext();

int recCount = db.Employee.Count();

var emp = (from E in db.Employee
           select E).Skip(recCount - 3);

var result = emp.ToList();

Fernando
0
 
LVL 1

Author Comment

by:Nargzul
ID: 33838986
@FernandoSoto: doing a .Count() load data no? I just can't afford me this
0
 
LVL 64

Accepted Solution

by:
Fernando Soto earned 2000 total points
ID: 33840442
Then the only way to do what you want is to reverse order the query and take the top 3, something like the following.

     var query = (from E in db.Employee
                         orderby E.EmployeeID descending
                         select E).Take(3);
0
 
LVL 1

Author Closing Comment

by:Nargzul
ID: 33840516
Not exactly I was expecting, though I think there is not better solution :/
0

Featured Post

Windows Server 2016: All you need to know

Learn about Hyper-V features that increase functionality and usability of Microsoft Windows Server 2016. Also, throughout this eBook, you’ll find some basic PowerShell examples that will help you leverage the scripts in your environments!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Performance in games development is paramount: every microsecond counts to be able to do everything in less than 33ms (aiming at 16ms). C# foreach statement is one of the worst performance killers, and here I explain why.
The article shows the basic steps of integrating an HTML theme template into an ASP.NET MVC project
In this brief tutorial Pawel from AdRem Software explains how you can quickly find out which services are running on your network, or what are the IP addresses of servers responsible for each service. Software used is freeware NetCrunch Tools (https…
Add bar graphs to Access queries using Unicode block characters. Graphs appear on every record in the color you want. Give life to numbers. Hopes this gives you ideas on visualizing your data in new ways ~ Create a calculated field in a query: …

721 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question