mongodb 实现关系型数据库中查询某一列 的效果

最近在tornado\mongodb\ansible

mongodb中有个find()方法很牛逼,可以将集合中所有的表都传出来,一开始我这么写

class Module_actionHandler(tornado.web.RequestHandler):
def get(self, *args, **kwargs):
coll = self.application.db.waitfish
hosts = coll.find({}, {'hostname':1,"_id":0})
modulenames = ['ping', 'setup', 'copy']
self.render(
"module_action.html",
hosts = hosts,
modulenames = modulenames,
)

然后在模板中:
<select name="hostname">
{% for host in hosts %}
<option name="{{ host['hostname'] }}" >{{ host['hostname'] }}</option>
{% end %}
</select>

后来想了想find()方法是找出所有的表,这太伤不起了..
于是又去看了度娘,基本上都是列出一大堆查询命令,好多中方法的.

最后我还是选了这一种:

class Module_actionHandler(tornado.web.RequestHandler):
def get(self, *args, **kwargs):
coll = self.application.db.waitfish
hosts = coll.find({}, {'hostname':1,"_id":0})#解释一下,这里hostname:1 表示返回hostname列,由于_id列每次都返回所以用0禁用掉,模板还一样
modulenames = ['ping', 'setup', 'copy']
self.render(
"module_action.html",
hosts = hosts,
modulenames = modulenames,
)