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Update in MongoDB and prevent overwrite?
Let us create a collection with documents −
> db.demo601.insertOne(
... {
... id:1,
... userDetails:
... {
... userName:"John",
... userMailId:"John@gmail.com"
... }
... }
... );
{
"acknowledged" : true,
"insertedId" : ObjectId("5e95ff5ced011c280a0905c7")
}
>
> db.demo601.insertOne( { id:2, userDetails: { userName:"Carol",
userMailId:"Carol@gmail.com" } } );{
"acknowledged" : true,
"insertedId" : ObjectId("5e95ff71ed011c280a0905c8")
}Display all documents from a collection with the help of find() method −
> db.demo601.find();
This will produce the following output −
{ "_id" : ObjectId("5e95ff5ced011c280a0905c7"), "id" : 1, "userDetails" : { "userName" : "John", "userMailId" : "John@gmail.com" } }
{ "_id" : ObjectId("5e95ff71ed011c280a0905c8"), "id" : 2, "userDetails" : { "userName" : "Carol", "userMailId" : "Carol@gmail.com" } }Following is the query to update −
>db.demo601.update({_id:ObjectId("5e95ff71ed011c280a0905c8")},{$set:{userMailId:"Carol@yahoo.com"}});
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })Display all documents from a collection with the help of find() method −
> db.demo601.find();
This will produce the following output −
{ "_id" : ObjectId("5e95ff5ced011c280a0905c7"), "id" : 1, "userDetails" :
{ "userName" : "John", "userMailId" : "John@gmail.com" }
}
{ "_id" : ObjectId("5e95ff71ed011c280a0905c8"), "id" : 2, "userDetails" :
{ "userName" : "Carol", "userMailId" : "Carol@gmail.com" }, "userMailId" : "Carol@yahoo.com"
}
Updated on: 15-May-2020
447 Views
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