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How to pull an array element (which is a document) in MongoDB?
You can use $pull operator. Let us first create a collection with documents −
> db.pullAnArrayElementDemo.insertOne( { "StudentDetails": [ { "StudentFirstName":"Chris","StudentScore":56 }, {"StudentFirstName":"Robert","StudentScore":59 } ] } );
{
"acknowledged" : true,
"insertedId" : ObjectId("5cd3b55bedc6604c74817cd5")
}Following is the query to display all documents from a collection with the help of find() method −
> db.pullAnArrayElementDemo.find().pretty();
This will produce the following output −
{
"_id" : ObjectId("5cd3b55bedc6604c74817cd5"),
"StudentDetails" : [
{
"StudentFirstName" : "Chris",
"StudentScore" : 56
},
{
"StudentFirstName" : "Robert",
"StudentScore" : 59
}
]
}Following is the query to pull an array element (which is a document) in MongoDB −
>db.pullAnArrayElementDemo.update({},{$pull:{'StudentDetails':{'StudentFirstName':'Chris'}}});
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })Let us display all the documents once again. The query is as follows −
> db.pullAnArrayElementDemo.find().pretty();
This will produce the following output −
{
"_id" : ObjectId("5cd3b55bedc6604c74817cd5"),
"StudentDetails" : [
{
"StudentFirstName" : "Robert",
"StudentScore" : 59
}
]
}
Updated on: 30-Jul-2019
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