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MongoDB query to set a sub item in an array?
You can use positional $ operator. Let us first create a collection with documents −
> db.demo22.insertOne(
... {
... ProductId:101,
...
... ProductDetails:
... [
... {
... ProductFirstPrice: '35',
... ProductSecondPrice: '75'
... },
... {
... ProductFirstPrice: '',
... ProductSecondPrice:''
... },
... {
... ProductFirstPrice: '78',
... ProductSecondPrice:'24'
... }
... ]
... }
...
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5e14c0b422d07d3b95082e70")
}Display all documents from a collection with the help of find() method −
> db.demo22.find().pretty();
This will produce the following output −
{
"_id" : ObjectId("5e14c0b422d07d3b95082e70"),
"ProductId" : 101,
"ProductDetails" : [
{
"ProductFirstPrice" : "35",
"ProductSecondPrice" : "75"
},
{
"ProductFirstPrice" : "",
"ProductSecondPrice" : ""
},
{
"ProductFirstPrice" : "78",
"ProductSecondPrice" : "24"
}
]
}Following is the MongoDB query to set a sub item in an array −
> db.demo22.update({ "ProductDetails.ProductFirstPrice" : "35" },
... { $set : { "ProductDetails.$.ProductFirstPrice" : "" }}, false, true);
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })Display all documents from a collection with the help of find() method −
> db.demo22.find().pretty();
This will produce the following output −
{
"_id" : ObjectId("5e14c0b422d07d3b95082e70"),
"ProductId" : 101,
"ProductDetails" : [
{
"ProductFirstPrice" : "",
"ProductSecondPrice" : "75"
},
{
"ProductFirstPrice" : "",
"ProductSecondPrice" : ""
},
{
"ProductFirstPrice" : "78",
"ProductSecondPrice" : "24"
}
]
}
Updated on: 01-Apr-2020
170 Views
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