MySql with MVC3 gives an error when calling context.savechanges

Question

I'm trying to get my MVC3 application to use MySql database instead of Sql Server 2008. I have created the associated database and objects in Mysql. And Updated the connection string in my web.config file to reference MySql.Data.MySqlClient.

When I run my application and try to login, I am getting the 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 have a custom MembershipProvider and within the validation process I have the following

 using (MyContext context= new MyContext())
 {
      --some checks here
      ---
        if (verificationSucceeded)
        {
            user.passwordFailuresSinceLastSuccess = 0;
        }
        else
        {
            int failures = user.passwordFailuresSinceLastSuccess;
            if (failures != -1)
            {
                user.passwordFailuresSinceLastSuccess += 1;
                user.lastPasswordFailureDate = DateTime.UtcNow;
            }
        }
        context.SaveChanges();  ----THIS IS WHERE IT FALLS OVER
         -- some other code here 
    }

The above code works perfectly well with Sql Server 2008, but is falling over only with MySql. Any idea how I can resolve this please?

I do not have any triggers defined on the underlying table btw. The application is MVC3 with EF Code First. Thanks,

Answer 1

If anybody else is having this issue, the problem was with the Guid as I though. To get over this, add the following to your connection string

Old Guids=true

So for example, my connection string looks like this now.

<add name="MyDB" connectionString="Server=localhost; Database=mydatabase; Uid=user; Pwd=mypass; Old Guids=true;" providerName="MySql.Data.MySqlClient" />