I am using MongoDB 6.0 and mongosh 1.5. I have a collection, which have elements with following structure:

{
    "name": "Optimization using NN",
    "calculations": {
        "1": {
            "code": "A123",
            "purpose": "TIME",
            "cities": {
                "PARIS": {
                    "load": 50,
                    "price": 10.45
                },
                "ROME": {
                    "load": 100,
                    "price": 8.25
                },
                "LYON": {
                    "load": 40,
                    "price": 9.00
                }
            }
        },
        "2": {
            "code": "B123",
            "purpose": "COST",
            "cities": {
                "PARIS": {
                    "load": 150,
                    "price": 9.45
                },
                "ROME": {
                    "load": 40,
                    "price": 7.25
                },
                "LYON": {
                    "load": 30,
                    "price": 8.00
                }
            }
        }
    }
}

I need to add field to every calculation, which is not really dificult:

db.experiment.updateMany({},
    [{
            $set: {
                'calculations': {
                    $objectToArray: '$calculations'
                }
            }
        }, {
            $addFields: {
                'calculations.v.active': {
                    $literal: true
                }
            }
        }, {
            $set: {
                'calculations': {
                    $arrayToObject: '$calculations'
                }
            }
        }

    ])

Is there some way to add field "constraints" with value of empty object to all cities?

{
    "name": "Optimization using NN",
    "calculations": {
        "1": {
            "code": "A123",
            "purpose": "TIME",
            "cities": {
                "PARIS": {
                    "load": 50,
                    "price": 10.45,
                    "constraints" : {}
                },
                "ROME": {
                    "load": 100,
                    "price": 8.25,
                    "constraints" : {}
                },
                "LYON": {
                    "load": 40,
                    "price": 9.00,
                    "constraints" : {}
                }
            },
            "active" : true
        },
        "2": {
            "code": "B123",
            "purpose": "COST",
            "cities": {
                "PARIS": {
                    "load": 150,
                    "price": 9.45,
                    "constraints" : {}
                },
                "ROME": {
                    "load": 40,
                    "price": 7.25,
                    "constraints" : {}
                },
                "LYON": {
                    "load": 30,
                    "price": 8.00,
                    "constraints" : {}
                }
            },
            "active" : true
        }
    }
}

I can't use $objectToArray again on '$calculations.v.cities', because it is already an array.

CodePudding user response：

Query

• you have data in keys in nested way also, so here $ObjectToArray and back to array, is needed in a nested way
• this produces the expected result, adds active : true in all calculations, and constraints : {} to all cities

*maybe query could be smaller, but in general queries that have data in the schema are complicated and slow, i suggest to change your schema

Playmongo

aggregate(
[{"$set": 
   {"calculations": 
     {"$map": 
       {"input": {"$objectToArray": "$calculations"},
        "as": "outer",
        "in": 
         {"k": "$$outer.k",
          "v": 
           {"$mergeObjects": 
             [{"active": true}, "$$outer.v",
               {"cities": 
                 {"$arrayToObject": 
                   [{"$map": 
                       {"input": {"$objectToArray": "$$outer.v.cities"},
                        "as": "inner",
                        "in": 
                         {"k": "$$inner.k",
                          "v": 
                           {"$mergeObjects": 
                             ["$$inner.v", {"constraints": {}}]}}}}]}}]}}}}}},
 {"$set": {"calculations": {"$arrayToObject": ["$calculations"]}}}])