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How to remove an element from a doubly-nested array in a MongoDB document?
To remove an element from a doubly-nested array in MongoDB document, you can use $pull operator.
To understand the concept, let us create a collection with the document. The query to create a collection with a document is as follows −
> db.removeElementFromDoublyNestedArrayDemo.insertOne(
... {
... "_id" : "1",
... "UserName" : "Larry",
... "UserDetails" : [
... {
... "UserCountryName" : "US",
... "UserLocation" : [
... {
... "UserCityName" : "New York"
... },
... {
... "UserZipCode" : "10001"
... }
... ]
... }
... ]
... }
... );
{ "acknowledged" : true, "insertedId" : "1" }
> db.removeElementFromDoublyNestedArrayDemo.insertOne(
... {
... "_id" : "2",
... "UserName" : "Mike",
... "UserDetails" : [
... {
... "UserCountryName" : "UK",
... "UserLocation" : [
... {
... "UserCityName" : "Bangor"
... },
... {
... "UserZipCode" : "20010"
... }
... ]
... }
... ]
... }
... );
{ "acknowledged" : true, "insertedId" : "2" }Display all documents from a collection with the help of find() method. The query is as follows −
> db.removeElementFromDoublyNestedArrayDemo.find().pretty();
The following is the output −
{
"_id" : "1",
"UserName" : "Larry",
"UserDetails" : [
{
"UserCountryName" : "US",
"UserLocation" : [
{
"UserCityName" : "New York"
},
{
"UserZipCode" : "10001"
}
]
}
]
}
{
"_id" : "2",
"UserName" : "Mike",
"UserDetails" : [
{
"UserCountryName" : "UK",
"UserLocation" : [
{
"UserCityName" : "Bangor"
},
{
"UserZipCode" : "20010"
}
]
}
]
}Here is the query to remove an element from a doubly-nested array in MongoDB document −
> db.removeElementFromDoublyNestedArrayDemo.update(
... { _id : "2" },
... {$pull : {"UserDetails.0.UserLocation" : {"UserZipCode":"20010"}}}
... );
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })Lets us check the documents from a collection with the help of find(). The query is as follows −
> db.removeElementFromDoublyNestedArrayDemo.find().pretty();
The following is the output −
{
"_id" : "1",
"UserName" : "Larry",
"UserDetails" : [
{
"UserCountryName" : "US",
"UserLocation" : [
{
"UserCityName" : "New York"
},
{
"UserZipCode" : "10001"
}
]
}
]
}
{
"_id" : "2",
"UserName" : "Mike",
"UserDetails" : [
{
"UserCountryName" : "UK",
"UserLocation" : [
{
"UserCityName" : "Bangor"
}
]
}
]
}Now field "UserZipCode": "20010" has been removed from a doubly-nested array.
Updated on: 30-Jul-2019
2K+ Views
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