mysql - python: query mongodb database to find a specific value under a unknown field -


i using python generate mongodb database collection , need find specific values database, document like:

{ "_id":objectid(215454541245), "category":food "venues":{"thai restaurant":251, "kfc":124, "chinese restaurant":21,.....} }

my question that, want query database , find venues have value smaller 200, in example, "kfc" , "chinese restaurant" returned query.

anyone knows how that?

if can change schema easier issue queries against collection. is, having dynamic values keys considered bad design pattern mongodb extremely difficult query.

a recommended approach follow embedded model this:

{     "_id": objectid("553799187174b8c402151d06"),     "category": "food",     "venues": [         {             "name": "thai restaurant",             "value": 251         },         {             "name": "kfc",             "value": 124         },         {             "name": "chinese restaurant",             "value": 21         }     ] }

thus structure issue query find venues have value smaller 200:

db.collection.findone({"venues.value": { "$lt": 200 } },      {         "venues": { "$elemmatch": { "value": { "$lt": 200 } } },         "_id": 0      });

this return result:

/* 0 */ {     "venues" : [          {             "name" : "kfc",             "value" : 124         }     ] }

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