Adding new element to array in MongoDb -

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i have mongodb collection this:-

{     "_id": objectid("52174bcb834806830e5447"),     "roles": [         {             "role": "admin"         },         {             "role": "user"         }     ] }

i need add new 'role' roles array. {"role": "guest" }. how do that?

you can $push-operator

this should work:

 db.collection.update(      { _id:  objectid("52174bcb834806830e5447") },      { $push: { roles: { role: "guest" } } }  );

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