Rename Field for All MongoDB Documents Using $rename Operator
Renaming a field Across all documents in MongoDB
To rename a field across all documents in a MongoDB collection, you use the $rename operator with the updateMany() method. This process changes the field's name for every document in the collection, which is often required when refactoring a database schema.
Syntax:
db.collection.updateMany( { /* filter (optional) */ }, { $rename: { "oldFieldName": "newFieldName" } } )
Explanation:
- db.collection: Replace collection with the name of your MongoDB collection.
- updateMany(): Used to update all documents that match the specified filter.
- $rename: MongoDB operator used to rename a field.
Example:
Here's a practical example that renames a field called username to user_name in all documents of a collection called users.
Code:
// Connect to the "users" collection and rename the "username" field to "user_name" in all documents
db.users.updateMany(
{}, // empty filter to target all documents
{ $rename: { "username": "user_name" } } // rename "username" to "user_name"
)
Explanation:
- db.users.updateMany:
- We use updateMany() on the users collection to target all documents. An empty filter {} is passed to apply the change to every document in the collection.
- { $rename: { "username": "user_name" } }:
- The $rename operator takes a mapping of old field names to new field names. Here, "username" will be renamed to "user_name" in every document.
After executing this command, each document in the users collection will have user_name instead of username.
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https://www.w3resource.com/mongodb/snippets/renaming-a-field-across-all-documents-in-mongodb.php
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