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Deleting specific record from an array nested within another array in MongoDB
To delete specific record, use “$pull” and since we are updating the already created collection, use UPDATE().
Let us create a collection with documents −
> db.demo213.insertOne({
... "id": 101,
... "details1": [
... {
... "Name": "Chris",
... "details2": [
... {
... "StudentName": "David",
... "Subject": "MongoDB"
... },
... {
... "StudentName": "Mike",
... "Subject": "MySQL"
... }
... ]
...
... }
... ]
...}
...);
{
"acknowledged" : true,
"insertedId" : ObjectId("5e3e300c03d395bdc2134704")
}Display all documents from a collection with the help of find() method −
> db.demo213.find().pretty();
This will produce the following output −
{
"_id" : ObjectId("5e3e300c03d395bdc2134704"),
"id" : 101,
"details1" : [
{
"Name" : "Chris",
"details2" : [
{
"StudentName" : "David",
"Subject" : "MongoDB"
},
{
"StudentName" : "Mike",
"Subject" : "MySQL"
}
]
}
]
}Following is the query to delete specific record from an array nested within another array −
> db.demo213.update({"id": 101, "details1.Name": "Chris"},
... {
... "$pull": {"details1.$.details2" : { "Subject": "MySQL" }}
... }, multi=true
...)
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })Display all documents from a collection with the help of find() method −
> db.demo213.find().pretty();
This will produce the following output −
{
"_id" : ObjectId("5e3e300c03d395bdc2134704"),
"id" : 101,
"details1" : [
{
"Name" : "Chris",
"details2" : [
{
"StudentName" : "David",
"Subject" : "MongoDB"
}
]
}
]
}
Updated on: 27-Mar-2020
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