EF giving error on inserting and updating child table record

Question

Inside story object i have child object rating i am getting issue while inserting new rating.

Erorr Message is "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."

enter image description here

   public async Task WriteRatingForStory(int storyId, int userId, int 
      score)
    {
        // Get the story that was rated
        var story = await _dbContext.Stories.FirstOrDefaultAsync(story => story.Id == storyId);

        // Updating thestory with the new rating
        story.WriteRating(userId, score);

        //_dbContext.Stories.Update(story);

        // Save the updated story to the database
        var saved = false;
        while (!saved)
        {
            try
            {
                // Attempt to save changes to the database

                _dbContext.SaveChanges();
                saved = true;
            }
            catch (DbUpdateConcurrencyException ex)
            { 
            }
         }
      } 

   public void WriteRating(int userId, double newRating)
       {

            Ratings.Add(new Rating() { StoryId = this.Id, Score = newRating, UserId = userId });
            AverageRating = ((AverageRating * NumberOfRatings - 1) + newRating) / NumberOfRatings;

    }

I'm not sure if this causes the error, but there is no need for the `_dbContext.Update(story)`. The story is already attached to the `_dbContext` (having been read from it) so any changes to it or associated objects will automatically be written to the DB on `SaveChanges()`. — Jasper Kent, Mar 23 '20 at 10:26
Error message is showing "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." — Karan Kumar, Mar 23 '20 at 10:27
since you aren't calling the update method you have to mark the entity as modified — HMZ, Mar 23 '20 at 15:40

score 0 · Answer 1 · answered Mar 23 '20 at 10:38

0

You are running asynchronised, so it doesn't wait for the commit you need to make it sync

answered Mar 23 '20 at 10:38

Daniel Rapaport

375
2
18

Implemented changes as per your suggestion but its not working – Karan Kumar Mar 23 '20 at 11:10
I updated the code description even you can check image for more detail https://i.stack.imgur.com/OegCQ.png – Karan Kumar Mar 23 '20 at 15:28
I would try await context.SaveChangesAsync(); instead of context.SaveChanges(); – Daniel Rapaport Mar 23 '20 at 20:38

EF giving error on inserting and updating child table record

1 Answers1