I have a large number of documents in mongoDB that need updating. Here are a few examples of existing documents from the Users collection:

{ 
    "_id" : "549120bcf5115900124fb6e1", 
    "user" : "Tom", 
    "country" : "United Kingdom", 
    "province" : "North Yorkshire", 
    "city" : "York", 
    "organization" : "" 
},
{ 
    "_id" : "143184fbf5482260184ac6e2", 
    "user" : "Jack", 
    "country" : "Not Listed", 
    "province" : "", 
    "city" : "", 
    "organization" : "United Nations"
},
{ 
    "_id" : "1234567890123456748979", 
    "user" : "Sarah", 
    "country" : "Not Listed", 
    "province" : "", 
    "city" : "", 
    "organization" : "" 
},
{ 
    "_id" : "98765432411654987654", 
    "user" : "Mat"
}

Each document may contain values for country, province, and city fields, or just country and state.

• a country, a province, and a city
• or a country and a state

Here is a sample from the Countries collection:

{ 
    "_id" : "123456789", 
    "key" : "Not Listed",
    "uuid" : "ca55b53a-ef5b-43ed-90ed-b857f45ddb6d",    
    "organization" : [
        {
            "key" : "United Nations", 
            "uuid" : "1c4ae4c6-00c5-405d-98fa-ca7cc9edc72a"
        }, 
        {
            "key" : "FIFA", 
            "uuid" : "11cfe606-821f-40fb-b1d0-bb7f9abb21dc"
        }
    ], 
    "province" : [], 
},
{ 
    "_id" : "1123465498742", 
    "key" : "United Kingdom", 
    "uuid" : "d756e167-25ec-4aa9-b231-4dbf6d4bfce4",
    "organization" : [], 
    "province" : [
        {
            "key" : "North Yorkshire", 
            "uuid" : "73d07c77-eba4-4dfa-9ada-e0ba8d8a2d55",            
            "city" : [
                {
                    "key" : "York", 
                    "uuid" : "80fd18a6-c4eb-4fb9-b591-6cca62319ba7"
                }, 
                {
                    "key" : "Middlesbrough", 
                    "uuid" : "26a277c4-8640-4959-a64a-00f3727975f4"
                }
            ], 
        },
        {
            "key" : "Oxfordshire", 
            "uuid" : "f7b5a570-df42-4520-ba3a-8bdcdd00e7d4",            
            "city" : [
                {
                    "key" : "Oxford", 
                    "uuid" : "b931865c-a363-4958-b7e7-5503fe674eb0"
                }, 
                {
                    "key" : "Banbury", 
                    "uuid" : "b8d4c63a-75a9-4c3c-a4cd-d315f06a92e0"
                }
            ], 
        }
    ]
}

The goal is to update the country/organization/province/city field values in the Users collection based on the uuid value from the Countries collection.

The updated documents will look like this:

{ 
    "_id" : "549120bcf5115900124fb6e1", 
    "user" : "Tom", 
    "country" : "d756e167-25ec-4aa9-b231-4dbf6d4bfce4", // uuid of United Kingdom
    "province" : "73d07c77-eba4-4dfa-9ada-e0ba8d8a2d55", // uuid of North Yorkshire
    "city" : "80fd18a6-c4eb-4fb9-b591-6cca62...
},
{ 
    "_id" : "143184fbf5482260184ac6e2", 
    "user" : "Jack", 
    "country" : "ca55b53a-ef5b-43ed-90ed-b857f45ddb6d", // uuid of Not Listed
    "province" : "", 
    "city" : "", 
    ...
},
{ 
    "_id" : "1234567890123456748979", 
    "user" : "Sarah", 
    "country" : "ca55b53a-ef5b-43ed-90ed-b857f45ddb6d", // uuid of Not Listed
    "province" : "", 
    "city" : "", 
    ...
},
{ 
    "_id" : "98765432411654987654", 
    "user" : "Mat" 
}

The fields have dependencies as follows:

Country > Province > City

Or:

Country > Organization

It's possible for a parent field to exist without its child field being present.

Is there a way to update these multidimensional arrays using MongoDB script rules?

Here is my attempt, which involves multiple nested loops. I'm unsure how to handle the find/update/save part in MongoDB... Can anyone provide guidance on achieving this?

var usrCountry, uuidcountry, usrProvince, uuidprovince, usrOrg, uuidorg, usrCity, uuidcity;

for (var i = 0; i < users.length; i++) {
   usrCountry = users[i].country;
   usrProvince = users[i].province;
   usrOrg = users[i].organization;
   usrCity = users[i].city;
   for (var j = 0; j < countries.length; j++) {
     if (countries[j].key === usrCountry) {
       uuidcountry = countries[j].uuid;
       console.log('uuidcountry: ', uuidcountry)
       if (countries[j].province.length){
         for (var k = 0; k < countries[j].province.length; k++) {
           if (countries[j].province[k].key === usrProvince){
            uuidprovince = countries[j].province[k].uuid;
            console.log('uuidprovince', uuidprovince)
            for (var l = 0; l < countries[j].province[k].city.length; l++) {
             if (countries[j].province[k].city[l].key === usrCity){
               uuidcity = countries[j].province[k].city[l].uuid
               console.log('uuidcity: ', uuidcity)
             }
            }  
           }

         }
       }
     }
   }
}