title: django insert a raw to msql
body: <p>I am a fresh hand at django. I want to insert a new row into MySQL database, but when I trying to do as following, it goes error.</p>
  
  <pre><code>from django.db import models
  ...
  class Msg(models.Model):
      MsgId = BigIntegerField(length = 20)
      ToUserName = CharField(max_length = 45)
      FromUserName = CharField(max_length = 45)
      Content = TextField(max_length = 1024, blank = True)
  ...
  db_entry = Msg(MsgId=received_MsgId, ToUserName=received_ToUserName,
                 FromUserName=received_FromUserName, MsgType=received_MsgType,
                 Content=received_Content)
  db_entry.save()
  </code></pre>
  
  <p>This following is the table <code>all_massages</code> existing in my database, and how can I add a new row to it, and what extra things I need to do.</p>
  
  <pre><code>+--------------+---------------------+------+-----+---------+-------+
  | Field        | Type                | Null | Key | Default | Extra |
  +--------------+---------------------+------+-----+---------+-------+
  | MsgId        | bigint(20) unsigned | NO   | PRI | NULL    |       |
  | ToUserName   | varchar(45)         | NO   |     | NULL    |       |
  | FromUserName | varchar(45)         | NO   |     | NULL    |       |
  | Content      | text                | YES  |     | NULL    |       |
  +--------------+---------------------+------+-----+---------+-------+
  </code></pre>