How to modify fields in specific sub-documents in an array? - arrays

Question

I have a collection where each document has an array of sub-documents, containing several fields. I need to update specific sub-documents based on their fields, but every attempt I've done so far changes the field in all of the arrayed sub-documents
Here is some sample data:
{
'_id' : ObjectId('0001'),
'Region' : 'Northern',
"Items" : [
{
"ItemId" : NumberInt(25),
"Name" : "Widget",
"ProductType" : "15",
"ItemIdLegacy" : "ca-000037"
},
{
"ItemId" : NumberInt(30),
"Name" : "Gizmo",
"ProductType" : "15",
"ItemIdLegacy" : "ca-000038"
},
{
"ItemId" : NumberInt(35),
"Name" : "Thingy",
"ProductType" : "15",
"ItemIdLegacy" : "ca-000039"
}
]
}
When I try to use update() with the following query, it updates the ProductType on all array items, not just the one I'm trying to change.
To clarify, I want to change the array item with ItemIdLegacy: "ca-000038" to have ProductType: 20. All other Array items should remain unchanged. Query that I have tried:
db.Collection.update({"Items.ItemIdLegacy" : "ca-000038"},[{$set: { "Items.ProductType" : "20"} }],{multi: false});
This is the desired output:
{
'_id' : ObjectId('0001'),
'Region' : 'Northern',
"Items" : [
{
"ItemId" : NumberInt(25),
"Name" : "Widget",
"ProductType" : "15",
"ItemIdLegacy" : "ca-000037"
},
{
"ItemId" : NumberInt(30),
"Name" : "Gizmo",
"ProductType" : "20",
"ItemIdLegacy" : "ca-000038"
},
{
"ItemId" : NumberInt(35),
"Name" : "Thingy",
"ProductType" : "15",
"ItemIdLegacy" : "ca-000039"
}
]
}
But this is the actual output of running that query:
{
'_id' : ObjectId('0001'),
'Region' : 'Northern',
"Items" : [
{
"ItemId" : NumberInt(25),
"Name" : "Widget",
"ProductType" : "20",
"ItemIdLegacy" : "ca-000037"
},
{
"ItemId" : NumberInt(30),
"Name" : "Gizmo",
"ProductType" : "20",
"ItemIdLegacy" : "ca-000038"
},
{
"ItemId" : NumberInt(35),
"Name" : "Thingy",
"ProductType" : "20",
"ItemIdLegacy" : "ca-000039"
}
]
}
I feel like I'm missing something simple...
EDIT: I have q uery that will allow me to update a single matching element in the array, but I have thousands that would need to be done so one offs don't necessarily work (sure I could parse them all out and spam them to the shell, but I want something more elegant)
Single Element Update:
db.Collection.updateOne({"Items.ItemIdLegacy" : "ca-000038"},{ $set: { "Items.$.ProductType" : "20" } } );

Answer 1

Try this :-
db.collection.update({
"Items.ItemIdLegacy": "ca-000038"
},
{
$set: {
"Items.$.ProductType": 20
}
},
{
multi: true
})
Here is Working Example