Entity Framework: “Store update, insert, or delete statement affected an unexpected number of rows (0).” [closed]

Answer 1

Check whether you forgot the "DataKeyNames" attribute in the GridView. it's a must when modifying data within the GridView

http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.gridview.datakeynames.aspx

Answer 2

The line [DatabaseGenerated(System.ComponentModel.DataAnnotations.DatabaseGeneratedOption.None)] did the trick in my case:

using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;


[Key]
[DatabaseGenerated(DatabaseGeneratedOption.None)]
public int? SomeNumber { get; set; }

Answer 3

Well i have this same issue. But this was due to my own mistake. Actually i was saving an object instead of adding it. So this was the conflict.

Answer 4

I was having same problem and @webtrifusion's answer helped find the solution.

My model was using the Bind(Exclude) attribute on the entity's ID which was causing the value of the entity's ID to be zero on HttpPost.

namespace OrderUp.Models
{
[Bind(Exclude = "OrderID")]
public class Order
{
    [ScaffoldColumn(false)]
    public int OrderID { get; set; }

    [ScaffoldColumn(false)]
    public System.DateTime OrderDate { get; set; }

    [Required(ErrorMessage = "Name is required")]
    public string Username { get; set; }
    }
}   

Answer 5

That's a side-effect of a feature called optimistic concurrency.

Not 100% sure how to turn it on/off in Entity Framework but basically what it's telling you is that between when you grabbed the data out of the database and when you saved your changes someone else has changed the data (Which meant when you went to save it 0 rows actually got updated). In SQL terms, their update query's where clause contains the original value of every field in the row, and if 0 rows are affected it knows something's gone wrong.

The idea behind it is that you won't end up overwriting a change that your application didn't know has happened - it's basically a little safety measure thrown in by .NET on all your updates.

If it's consistent, odds are it's happening within your own logic (EG: You're actually updating the data yourself in another method in-between the select and the update), but it could be simply a race condition between two applications.

Answer 6

None of the above answers quite covered my situation and the solution to it.

Code where the error was thrown in MVC5 controller:

        if (ModelState.IsValid)
        {
            db.Entry(object).State = EntityState.Modified; 
            db.SaveChanges(); // line that threw exception
            return RedirectToAction("Index");
        }

I received this exception when I was saving an object off an Edit view. The reason it threw it was because when I went back to save it, I had modified the properties that formed the primary key on the object. Thus, setting its state to Modified didn't make any sense to EF - it was a new entry, not a previously saved one.

You can solve this by either A) modifying the save call to Add the object, or B) just don't change the primary key on edit. I did B).