Random Records

[Jay]

Is there anyway to completely randomize the result set like sql server's "order by newid()" trick?

[Petko_I]

Hello Jay,

The randomization in a LINQ query cannot be propagated to the database server with OpenAccess. However, if you retrieve the persistent objects in memory, you can benefit from the LINQ to Objects implementation. You can then order your items by a random number generated with the Random class.

using (NorthwindContext context = new NorthwindContext())
{
    Random random = new Random();
    var query = context.Categories;
    var orderedQuery = query.ToList().OrderBy(x => random.Next());
    foreach (var category in orderedQuery)
    {
        Console.WriteLine(category.CategoryName);
    }
}

There is another option which is situationally useful – you can create a view which performs the ordering on the database server side and map it to a persistent type. Each time you retrieve a collection of persistent objects from this view, you will get them in a random order unless you order them explicitly.

I hope this helps. Do not hesitate to contact us if you have more questions.

Regards,
Petko_I
the Telerik team

[Markus]

I am not sure if this might be related to your questions but I had to get a random number of records from a DB and did it like this.

... .OrderBy(x => Guid.NewGuid()).Take(3);

works like a charm for me.

Markus

public virtual IQueryable<zuol_mobile.T_banner> GetRandomBanners()

       {

 

           var Banners = repository.GetAllBy(p => p.BannerID != 1).OrderBy(x => Guid.NewGuid()).Take(3);

 

           if (Banners == null)

           {

               throw new HttpResponseException(HttpStatusCode.MethodNotAllowed);

           }

 

           return Banners;

       }