EF Core database operation throws error "Data may have been modified or deleted since entities were loaded"

Question

I am using EF Core 3.1 have the following code

public void Update()
{
    Client client = new Client();
    client.ClientId = 1;
    client.Name = "New Client 1";

    dbContext.Entry<Client>(client).State = EntityState.Modified;
    dbContext.Entry<Client>(client).Property(x => x.IdentityNumber).IsModified = false;

    dbContext.SaveChanges();
}

which produces the following SQL an successfully updates the column

UPDATE [Client] 
SET [Name] = @p0
WHERE [ClientId] = @p1;

SELECT @@ROWCOUNT;

However when I change the ClientId = 4 which is an entry that was deleted from database it produces the same SQL query but throws the following error

Database operation expected to affect 1 row(s) but actually affected 0 row(s). Data may have been modified or deleted since entities were loaded

The error message is clear but I don't understand why it does not work as SQL Server works (0 row(s) affected) and instead throws this error.

How can I simulate the 0 row(s) affected SQL Server behavior using EF Core?

I do not want to query the database first if the row exists and then update. The above code is a sample. In my methods I have lists with many clients that I need to update at once and it takes long to do that using the first check if exists and then update.

I'm guessing it is because you are changing it to update when a record of that id does not exist. you need to insert the record before you can update. — Hogan
@Hogan if you read my post carefully I state that the record was deleted — pantonis
I was not sure but if the record has been deleted how do you expect to update it? — Hogan

brnlmrry brnlmrry · Accepted Answer · 2019-12-18T20:23:27

I do not want to query the database first if the row exists and then update.

This is the crux of your problem and the reason for the error.

Our approach, and a common one I believe, is to use Dapper when manipulating a lot of data, and limit EF to Load -> Edit -> Save operations on single or very few entities.

EF Core database operation throws error "Data may have been modified or deleted since entities were loaded"

1 Answers