I am new to mongoDB need a query to delete the collections - mongodb

Question

I have two collections.
1.Equipment
db.getCollection("Equipment").find({
$and: [
{ $where: 'this._id.length <= 7' },
{ "model": "A505"}
]})
{
"_id" : "1234567",
"locationId" : "DATALOAD",
"model" : "A505",
"subscriberId" : "",
"status" : "Stock",
"headendNumber" : "4"
}
{
"_id" : "P13050I",
"locationId" : "1423110302801",
"model" : "A505",
"subscriberId" : "37",
"status" : "Stock",
"headendNumber" : "4"
}
I will get more than 100 documents (rows) Equipment collection.
2.Subscriber
db.getCollection('Subscriber').find({})
{
"_id" : "5622351",
"equipment" : [
"0018015094E6",
"1234567",
"ADFB70878422",
"M10610TCB052",
"MA1113FHQ151"
]
}
{
"_id" : "490001508063",
"equipment" : [
"17616644510288",
"P13050I",
"M91416EA4251",
"128552270280560"
]
}
In the Subscriber collection, I need to remove (get all the id from Equipment collection loop it) only the matches equipment field.
Forex from the above result, I need to remove only "1234567", and "P13050I"
Expected output.
db.getCollection('Subscriber').find({})
{
"_id" : "5622351",
"equipment" : [
"0018015094E6",
"ADFB70878422",
"M10610TCB052",
"MA1113FHQ151"
]
}
{
"_id" : "490001508063",
"equipment" : [
"17616644510288",
"M91416EA4251",
"128552270280560"
]
}
Please help me, anyone.

Answer 1

You can use the following to update records.
Let's find records which need to deleted and store them in array
var equipments = [];
db.getCollection("Equipment").find({ $and: [
{ $where: 'this._id.length <= 7' },
{ "model": "A505"}
]}).forEach(function(item) => {
equipments.push(item._id)
})
Now, iterate over records of the second collection and update if required.
db.getCollection('Subscriber').find({}).forEach(function(document) => {
var filtered = document.equiment.filter(id => equipments.indexOf(id) < 0);
if(filtered.length < document.equipment.length){
db.getCollection('Subscriber').update({"_id": document.id }, { $set: {'equipment': filtered}})
}
})
.filter(id => equipments.indexOf(id) < 0) will keep entries which is not present in initially populated array equipments and it will persist if there is any change.