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 = col

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,
 )

 {% for host in hosts %}
 {{ host['hostname'] }}
 {% end %}

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,
 )