Updating a nested Array in using UpdateOne() - mongodb

Question

I'm having an issue updating a nested Array in a document. Reading around the topic i've come across various method, one that i've tweaked below, however nothing seems to work for me!
I'm trying to update the field systemUpdate_DT which is in a parent Array called List and a child array called customData. I'm referring to the object in the child array using the key _id of the parent array and key field_id in the child array.
How do I update the systemUpdate_DT of the respective object?
Live Example: https://mongoplayground.net/p/453OFPOQqBp
A document in the collection looks like:
[
{
"_id": "6032a5ad80443334a35f2232",
"List": [
{
"_id": "6032a5af80443334a35f2234",
"customData": [
{
"_id": "6032a5bc80443334a35f223c",
"systemUpdate_DT": null,
"field_id": "6032a5bc80443334a35f223b"
},
{
"_id": "6032a5c280443334a35f223e",
"systemUpdate_DT": null,
"field_id": "6032a5c280443334a35f223d"
}
]
},
{
"_id": "6032a5b080443334a35f2236",
"customData": [
{
"_id": "6032a5bc80443334a35f223c",
"systemUpdate_DT": null,
"field_id": "6032a5bc80443334a35f223b"
},
{
"_id": "6032a5c280443334a35f223e",
"systemUpdate_DT": null,
"field_id": "6032a5c280443334a35f223d"
}
]
}
]
}
]
My Update Query looks like:
db.collection.updateOne({
{
"List._id": mongodb.ObjectId("6032a5af80443334a35f2234"),
"List.customData.field_id": mongodb.ObjectId("6032a5bc80443334a35f223b")
},
{
$set: {
"List.$.customData.systemUpdate_DT": 'updatedDTTM'
}
})

Answer 1

As there's two nested arrays in your document, you can't set the field with classic positional operator '$'.
Instead, you should use the arrayFilters option like this:
db.collection.update({
"_id": ObjectId("6032a5ad80443334a35f2232")
},
{
$set: {
"List.$[list].customData.$[customData].systemUpdate_DT": "updatedDTTM"
}
},
{
"multi": false,
"upsert": false,
arrayFilters: [
{
"list._id": {
"$eq": ObjectId("6032a5af80443334a35f2234")
}
},
{
"customData._id": {
"$eq": ObjectId("6032a5bc80443334a35f223c")
}
}
]
})
try it online: mongoplayground.net/p/fb_86rNUKvt