title: Update existing row mysql linq
body: <p>I have html page with table. When I change field I need to re-save existing record in table.</p>
  
  <pre><code>public int SaveTask(TimesheetListModel task, int userId)
  {
      var worklog = new tblWorkLog();
  
      if (task != null)
      {
          worklog.AccountId = userId;     
          worklog.WorkDate = task.Date;
          worklog.Note = task.Note;       
          worklog.TaskTitle = task.Task;
  
          DataContext.tblWorkLogs.InsertOnSubmit(worklog);
  
          DataContext.SubmitChanges(ConflictMode.FailOnFirstConflict);
      }
  
      return worklog.WorkItemId;
  }
  </code></pre>
  
  <p>This function saves data to table <code>tblWorklogs</code> and returns me id of record. But when I updating record, I already have id of record and I need to find this record in table and update fields. How to do this? I wrote begin function:</p>
  
  <pre><code>public bool UpdateTask(TimesheetListModel task)
  {
      /* If update succefull must return true */
      return false;
  }
  </code></pre>