使用Linq to Entity删除多行的有效方法？

Question

Hi I'm looking for efficient way to delete multiple records at once. I'm deleting 400 records and it takes 8-15 seconds. Here is my code

using (var entities = new Entity())
   {                               
       foreach (Item item in entities.Items.Where(x => x.id == id))
              entities.DeleteObject(item);
       entities.SaveChanges();
   }

Answer 1

You can do it faster using EntityFramework.Extensions
1) First install EntityFramework.Extensions using NuGet

2) Here is the code similar to Linq2Sql's DeleteAllOnSubmit():

using EntityFramework.Extensions;

....

using (var entities = new Entity())
{                               
    entities.Items.Delete(x => x.id == id);
    entities.SaveChanges();
}

...

Answer 2

In your loop:

using (var entities = new Entity()) 
{                                
    foreach (Item item in entities.Items.Where(x => x.id == id)) 
           entities.DeleteObject(item); 
    entities.SaveChanges(); 
} 

If you move the entities.SaveChanges(); so that it runs after the loop, it will run substantially faster.

using (var entities = new Entity()) 
{                                
    foreach (Item item in entities.Items.Where(x => x.id == id)) 
          entities.DeleteObject(item); 
} 
entities.SaveChanges(); 

Answer 3

Check out Bulk-deleting in LINQ to Entities or PLINQO for Entity Framework if it's the sort of delete you could do in a single batch, ie

DELETE FROM Entities WHERE [some condition]

Otherwise, maybe check you've got an index on the x column you're using to find each record.