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Changing the primary key on a MongoDB collection?
To change the primary key, you need to first delete it. Use forEach() along with delete to remove and then get a new primary key. Let us create a collection with documents −
> db.demo41.insertOne({"StudentName":"Carol"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e25ce4acfb11e5c34d898e3")
}Display all documents from a collection with the help of find() method −
> db.demo41.find();
This will produce the following output −
{ "_id" : ObjectId("5e25ce4acfb11e5c34d898e3"), "StudentName" : "Carol" }Here is the query to change the primary key on a MongoDB collection −
> var next = db.demo41.find()
>
> next.forEach(function(s) {
... var prevId=s._id;
... delete s._id;
... db.demo41.insert(s);
... db.demo41.remove(prevId);
... });Let us check the primary key once again −
> db.demo41.find();
This will produce the following output displaying a new primary key −
{ "_id" : ObjectId("5e25cee5cfb11e5c34d898e4"), "StudentName" : "Carol" }
Updated on: 02-Apr-2020
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