How to delete particular data in a document in MongoDB?

You can use $unset. Let us first create a collection with documents −

> db.demo20.insertOne(
...    {
...
...       "ListOfEmployee" : [
...          {
...             "EmployeeName1" : "John"
...          },
...          {
...             "EmployeeName2" : "Carol"
...          }
...       ],
...       "EmployeeName2" : []
...    }
... );
{
   "acknowledged" : true,
   "insertedId" : ObjectId("5e138c3555d0fc6657d21f12")
}

Following is the query to display all documents from a collection with the help of find() method −

> db.demo20.find();

This will produce the following output −

{ "_id" : ObjectId("5e138c3555d0fc6657d21f12"), "ListOfEmployee" : [ { "EmployeeName1" : "John" }, { "EmployeeName2" : "Carol" } ], "EmployeeName2" : [ ] }

Following is the query to delete particular data in a document −

> db.demo20.update({ "EmployeeName2": { "$exists": 1 }},{ "$unset": { "EmployeeName2": "" } });
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

Following is the query to display all documents from a collection with the help of find() method −

> db.demo20.find();

This will produce the following output −

{ "_id" : ObjectId("5e138c3555d0fc6657d21f12"), "ListOfEmployee" : [ { "EmployeeName1" : "John" }, { "EmployeeName2" : "Carol" } ] }

AmitDiwan

Published on 01-Apr-2020 14:31:26

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