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

0 votes
asked Dec 2, 2009 by strongopinions

I am using Entity Framework to populate a grid control. Sometimes when I make updates I get the following error:

Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. Refresh ObjectStateManager entries.

I can't figure out how to reproduce this. But it might have something to do with how close together I make the updates. Has anyone seen this or does anyone know what the error message refers to?

Edit: Unfortunately I am no longer at liberty to reproduce the problem I was having here, because I stepped away from this project and don't remember if I eventually found a solution, if another developer fixed it, or if I worked around it. Therefore I cannot accept any answers.

30 Answers

0 votes
answered Dec 2, 2009 by fyjham

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.

0 votes
answered Jan 26, 2010 by paulo

You need to explicitly include a BoundField of the primary key. If you don't want the user to see the primary key, you have to hide it via css:

    <asp:BoundField DataField="Id_primary_key" ItemStyle-CssClass="hidden" 
HeaderStyle-CssClass="hidden" />

Where 'hidden' is a class in css that has it's display set to 'none'.

0 votes
answered Jan 20, 2011 by mubarak

If you are trying to create mapping in your edmx file to a "function Imports", this can result this error. Just clear the fields for insert, update and delete that is located in Mapping Details for a given entity in your edmx, and it should work. I hope I made it clear.

0 votes
answered Jan 25, 2011 by talimite

I ran into this using Telerik's RadGrid. I had the primary key as a gridbound column that was set to read only. It would work fine if the column was display="false" but readonly="true" caused the problem. I solved it by having the gridbound column display=false and adding a separate template column for display

<telerik:GridBoundColumn HeaderText="Shouldnt see" Display="false" 
     UniqueName="Id" DataField="Id">
</telerik:GridBoundColumn>
<telerik:GridTemplateColumn HeaderText="Id" UniqueName="IdDisplay">
    <ItemTemplate>
        <asp:Label ID="IDLabel" runat="server" 
            Text='<%# Eval("Id") %>'></asp:Label>                               
    </ItemTemplate>
</telerik:GridTemplateColumn> 
0 votes
answered Dec 13, 2011 by webtrifusion

I ran into this and it was caused by the entity's ID (key) field not being set. Thus when the context went to save the data, it could not find an ID = 0. Be sure to place a break point in your update statement and verify that the entity's ID has been set.

From Paul Bellora's comment

I had this exact issue, caused by forgetting to include the hidden ID input in the .cshtml edit page

0 votes
answered Dec 17, 2011 by pure-krome

The issue is caused by either one of two things :-

  1. You tried to update a row with one or more properties are Concurrency Mode: Fixed .. and the Optimistic Concurrency prevented the data from being saved. Ie. some changed the row data between the time you received the server data and when you saved your server data.
  2. You tried to update or delete a row but the row doesn't exist. Another example of someone changing the data (in this case, removing) in between a retrieve then save OR you're flat our trying to update a field which is not an Identity (ie. StoreGeneratedPattern = Computed) and that row doesn't exist.
0 votes
answered Dec 27, 2011 by solly

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

0 votes
answered Jan 4, 2012 by patrick

In our case this error was caused by marking entities as modified when none of their properties 'really' changed. For example when you assign same value to a property, context may see that as an update where database doesn't.

Basically we ran a script to repopulate one property with concatenated values from other properties. For a lot of records that meant no change, but it flagged them as modified. DB returned different number of updated objects which presumably triggered that exception.

We solved it by checking the property value and only assigning new one if different.

0 votes
answered Jan 5, 2012 by arun-aravind

While editing include the id or primary key of the entity as a hidden field in the view

ie

      @Html.HiddenFor(m => m.Id)

that solves the problem.

Also if your model includes non-used item include that too and post that to the controller

0 votes
answered Jan 8, 2012 by paul-zahra

Got this error when using SaveChanges(false) and then later SaveChanges() on the same context, in a unitofwork where multiple rows were being deleted from two tables (in the context)(SaveChanges(False) was in one of the deletes. Then in the calling function SaveChanges() was being called.... The solution was to remove the unnecessary SaveChanges(false).

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