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Clone a collection in MongoDB?
To clone a collection in MongoDB, you can use the forEach() method. Let us first create a collection with a document.
The query to create a collection with a document is as follows −
> db.studentInformation.insertOne({"StudentName":"Chris"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c8bc15780f10143d8431e21")
}
> db.studentInformation.insertOne({"StudentName":"Robert"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c8bc15e80f10143d8431e22")
}
> db.studentInformation.insertOne({"StudentName":"James"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5c8bc17380f10143d8431e23")
}Display all documents from a collection with the help of find() method. The query is as follows −
> db.studentInformation.find().pretty();
The following is the output −
{ "_id" : ObjectId("5c8bc15780f10143d8431e21"), "StudentName" : "Chris" }
{ "_id" : ObjectId("5c8bc15e80f10143d8431e22"), "StudentName" : "Robert" }
{ "_id" : ObjectId("5c8bc17380f10143d8431e23"), "StudentName" : "James" }Here is the query to make a clone in MongoDB −
> db.studentInformation.find().forEach( function(copyValue){db.makingStudentInformationClone.insert(copyValue)} );Let us check the documents of clone collection in MongoDB. The query is as follows −
> db.makingStudentInformationClone.find();
The following is the output −
{ "_id" : ObjectId("5c8bc15780f10143d8431e21"), "StudentName" : "Chris" }
{ "_id" : ObjectId("5c8bc15e80f10143d8431e22"), "StudentName" : "Robert" }
{ "_id" : ObjectId("5c8bc17380f10143d8431e23"), "StudentName" : "James" }Let us now check the list of all collections including clone. The query is as follows −
> show collections;
The following is the output −
copyThisCollectionToSampleDatabaseDemo deleteDocuments deleteDocumentsDemo deleteSomeInformation employee getElementWithMaxIdDemo internalArraySizeDemo makingStudentInformationClone prettyDemo selectWhereInDemo sourceCollection studentInformation updateInformation userInformation
Updated on: 30-Jul-2019
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