django foreignkey包含查询

我有下面的型号

class Command(models.Model):
    server = models.ForeignKey(Server)
    user_login = models.CharField(max_length=100)
    user_run = models.CharField(max_length=100)
    host = models.CharField(max_length=100)
    ip = models.CharField(max_length=100)
    session = models.CharField(max_length=100)
    command = models.TextField()
    ts = models.DateTimeField(auto_now_add=True)
    version = models.CharField(max_length=100)
    type = models.CharField(max_length=100)

我有以下搜索查询

cmds = Command.objects.filter(Q(user_login__contains=form.cleaned_data['loguser']),
                              Q(user_run__contains=form.cleaned_data['runuser']),
                              Q(host__contains=form.cleaned_data['loghost']),
                              Q(command__contains=form.cleaned_data['command']),
                              Q(server__contains=form.cleaned_data['host']),
                              Q(session__contains=form.cleaned_data['session'])) \
                      .order_by('-id')[:100]

我需要按以下字符串搜索server.host

如果我尝试添加以下内容，我会得到一个错误

Q(server__contains=form.cleaned_data['host']),

Exception Type:     TypeError
Exception Value:    

Related Field has invalid lookup: contains

Exception Location:     /usr/lib/python2.5/site-packages/django/db/models/fields/related.py in get_db_prep_lookup, line 156

form.cleaned_数据['host']将包含主机名的文本字符串

server__searchfieldname__contains

---

您没有指定服务器表中应该查找的字段。

您能提供一些文档链接吗？