I have following structure of my document:
{
"daily": [
{
"general": [
{
"status": false,
"_id": "5e728265f4796c0017203662",
"title": "Sport"
},...
]
}
]
}
I would like to pull the the document inside the "general" Array by it's "_id".
I tried several things but nothing seems to work for me.
Every help will be appreciate :)
The update query to pull the sub-document from the nested array field general using the _id:
ID = "5e728265f4796c0017203662"
db.collection.update(
{ "daily.general._id": ID },
{ $pull: { "daily.$.general": { _id: ID } } }
)
_id is typically an ObjectId, so I assume it should be rather ID = ObjectId("5e728265f4796c0017203662")This can only be done in Mongo 4.2+, where they introduced pipeline'd updates.
Now we can use aggregation expressions to update documents:
db.collection.updateOne(
{},
[
{
$set: {
"daily": {
$map: {
input: "$daily",
as: "item",
in: {
"general": {
$filter: {
input: "$$item.general",
as: "datum",
cond: {$ne: ["$$datum._id", "5e728265f4796c0017203662"]}
}
}
}
}
}
}
}
]);
Or if objects in daily have more than just the general field you can do it like this:
db.collection.updateOne(
{},
[
{
$set: {
"daily": {
$map: {
input: "$daily",
as: "item",
in: {
$mergeObjects: [
"$$item",
{
"general": {
$filter: {
input: "$$item.general",
as: "datum",
cond: {$ne: ["$$datum._id", "5e728265f4796c0017203662"]}
}
}
}
]
}
}
}
}
}
]);
Unfortunately for any other Mongo version this is not possible, you'll have to restructure your data or do it in code.
$[<identifier>] was introduced in Mongo 3.6