LINQ Delete multiple rows

Question

I am trying to delete multiple rows as such. The following code does the trick but kind of worries as the ForEach seems to indicate it may delete more than what the Where clause has. Is there a better way to do this or is the coding below sound?

db.task_Commt.Where(u => u.GlobalId == companyId
    && u.ItemId == itemId).ToList().ForEach(db.task_task_Commt.DeleteObject);

Why do you think it deletes more than the `Where` returns? Doesn't seem likely. — Gert Arnold, May 26 '15 at 20:20

Brino · Answer 1 · 2015-05-26T19:19:59.743

Use the RemoveRange() function of EF 6, to remove a IQueryable subset of the entities. This will mark each of the entities as deleted, and will delete them when the context is saved. This will be more efficient because it does not require you to enumerate the entities first.

using(context db = new context()){
    var items = db.task_Commt.Where(u => u.GlobalId == companyId && u.ItemId == itemId);
    db.task_Commt.RemoveRange(items);
    db.SaveChanges();
}

score 0 · Answer 2 · answered May 26 '15 at 19:11

Well, functionally this would be the same but it is (arguably) easier to understand what's happening:

 var itemsToDelete = db.task_Commt.Where(u => u.GlobalId == companyId 
                                      && u.ItemId == itemId)
 foreach(var d in itemsToDelete)
     db.task_task_Commt.DeleteObject(d);

Other benefits:

easier to debug since you can break on each item in the collection
it does not require hydrating to a list
no concerns about lambda closure
Using List.Foreach is generally discouraged since it offer little benefit over a normal foreach block.

LINQ Delete multiple rows

2 Answers2