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")