Delete a big list of items with Entity Framework [duplicate]

Question

I want to delete a big list of items with EF, so I tried to remove them one by one but it take long time.

And I tried to use .RemoveAll() method with my list but it don't update the database [only remove from loaded entity]

So I use a SqlCommand to remove them from the database and I use .RemoveAll() to prevent EF unexpected number of rows update (0) exception.

Code:

dbContext.Database.ExecuteSqlCommand("DELETE FROM xxx WHERE xxx");
loadedEntity.subItems.ToList().RemoveAll(r => true);
dbContext.SaveChanges();

My question: is there a better way to do this?

I update the question, I don't want to delete all Items in table I just want to delete all sub Items. IE: delete all products inside market. — user1150331
– user1150331, Commented Nov 13, 2014 at 10:26

user4093832 · Accepted Answer · 2014-11-13 09:34:39Z

27

try this

var all = dbContext.XXX.Where(x => x.xxx == "xxx");
dbContext.XXX.RemoveRange(all);
dbContext.SaveChanges();

answered Nov 13, 2014 at 9:34

user4093832

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4 Comments

user1150331 Over a year ago

I don't have this method .RemoveRange() in my dbContect

user4093832 Over a year ago

@user1150331 update your ef to 6.0 and you will get .

paulsm4 Over a year ago

Note - this is still a good response for EF/.Net Core, circa 2020.

Sean Haddy Over a year ago

Still works great 23'!

Vladimirs · Accepted Answer · 2014-11-13 10:43:01Z

1

Have a look at batch extensions. (one or two)

Deletion will be as simply as dbContext.XXX.Delete(x => x.xxx == "xxx").

edited Nov 13, 2014 at 10:43

answered Nov 13, 2014 at 9:23

Vladimirs

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Comments

Nguyen Van Thanh · Accepted Answer · 2020-01-07 08:03:30Z

0

Entity Framework Core

3.1 3.0 2.2 2.1 2.0 1.1 1.0

using (YourContext db = new YourContext())
{
    var foundList=db.YourDbSet.Where(c=>c.YourProp=='someVal').ToList();
    db.YourDbSet.RemoveRange(foundList);
    db.SaveChanges();
}

Summary:

Removes the given collection of entities from the context underlying the set with each entity being put into the Deleted state such that it will be deleted from the database when SaveChanges is called.

Remarks:

Note that if System.Data.Entity.Infrastructure.DbContextConfiguration.AutoDetectChangesEnabled is set to true (which is the default), then DetectChanges will be called once before delete any entities and will not be called again. This means that in some situations RemoveRange may perform significantly better than calling Remove multiple times would do. Note that if any entity exists in the context in the Added state, then this method will cause it to be detached from the context. This is because an Added entity is assumed not to exist in the database such that trying to delete it does not make sense.

answered Jan 7, 2020 at 8:03

Nguyen Van Thanh

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2 Comments

paulsm4 Over a year ago

You're correct. But... 1) that's basically what user4093832 already said above (six years ago), and 2) More often than not you'll probably already have a dbContext - there's seldom a need for "using/new Context()" in most "real world" code.

Nguyen Van Thanh Over a year ago

Sorry for making you confusing. 1. I learned it from Microsoft. 2. It is really for the OP 's example. Thank you.

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