MongoDB – copyTo() Method

In MongoDB, copyTo() method is used to copies all the documents from one collection(Source collection) to another collection(Target collection) using server-side JavaScript and if that other collection(Target collection) is not present then MongoDB creates a new collection with that name. This method uses eval command internally.     

Important Note: As CopyTo() uses eval() internally & eval() is deprecated since version 3.0, so CopyTo() is also deprecated since version 3.0.

Syntax:

db.sourceCollection.copyTo(targetCollection)                                                                   

Parameter:

It takes only the name of the target collection where you want to copy the documents of the source collection. The type of this parameter is string.

Return: 

This method returns the number of documents copied and if that process fails it throws an exception.

Example 1: In the following example, we are working with:

Database: gfg

Collections: collectionA and collectionB

The collectionA contains three documents:

The collectionB contains two documents:

Now we copy the documents of collectionA to collectionB using copyTo() method.

db.collectionA.copyTo("collectionB")

Example 2: In the following example, we are working with:

Database: gfg

Collection: sCollection

Documents: Three documents contains name and age of the students

Now we going to copy the documents of sCollection to a new collection i.e., tCollection using copyTo() method. Here, the tCollection is not present in gfg database so MongoDB create this collection.

db.sCollection.copyTo("tCollection")