How do you rename a MongoDB database?

问题:

There's a typo in my MongoDB database name and I'm looking to rename the database.

I can copy and delete like so...

db.copyDatabase('old_name', 'new_name');
use old_name
db.dropDatabase();

Is there a command to rename a database?

回答1:

No there isn't. See https://jira.mongodb.org/browse/SERVER-701

Unfortunately, this is not an simple feature for us to implement due to the way that database metadata is stored in the original (default) storage engine. In MMAPv1 files, the namespace (e.g.: dbName.collection) that describes every single collection and index includes the database name, so to rename a set of database files, every single namespace string would have to be rewritten. This impacts:

• the .ns file
• every single numbered file for the collection
• the namespace for every index
• internal unique names of each collection and index
• contents of system.namespaces and system.indexes (or their equivalents in the future)
• other locations I may be missing

This is just to accomplish a rename of a single database in a standalone mongod instance. For replica sets the above would need to be done on every replica node, plus on each node every single oplog entry that refers this database would have to be somehow invalidated or rewritten, and then if it's a sharded cluster, one also needs to add these changes to every shard if the DB is sharded, plus the config servers have all the shard metadata in terms of namespaces with their full names.

There would be absolutely no way to do this on a live system.

To do it offline, it would require re-writing every single database file to accommodate the new name, and at that point it would be as slow as the current "copydb" command...

回答2:

You could do this:

db.copyDatabase("db_to_rename","db_renamed","localhost")
use db_to_rename
db.dropDatabase();

Editorial Note: this is the same approach used in the question itself but has proven useful to others regardless.

回答3:

Alternative solution: you can dump your db and restore that in different name. As I've experienced it's much quicker than db.copyDatabase().

$ mongodump -d old_db_name -o mongodump/
$ mongorestore -d new_db_name mongodump/old_db_name

http://docs.mongodb.org/manual/tutorial/backup-with-mongodump/

回答4:

ALERT: Hey folks just be careful while copying the database, if you don't want to mess up the different collections under single database.

The following shows you how to rename

> show dbs;
testing
games
movies

To rename you use the following syntax

db.copyDatabase("old db name","new db name")

Example:

db.copyDatabase('testing','newTesting')

Now you can safely delete the old db by the following way

use testing;

db.dropDatabase(); //Here the db **testing** is deleted successfully

Now just think what happens if you try renaming the new database name with existing database name

Example:

db.copyDatabase('testing','movies'); 

So in this context all the collections (tables) of testing will be copied to movies database.

回答5:

The above process is slow,you can use below method but you need to move collection by collection to another db.

use admin
db.runCommand({renameCollection: "[db_old_name].[collection_name]", to: "[db_new_name].[collection_name]"})

回答6:

In the case you put all your data in the admin database (you shouldn't), you'll notice db.copyDatabase() won't work because your user requires a lot of privileges you probably don't want to give it. Here is a script to copy the database manually:

use old_db
db.getCollectionNames().forEach(function(collName) {
    db[collName].find().forEach(function(d){
        db.getSiblingDB('new_db')[collName].insert(d); 
    }) 
});

回答7:

Although Mongodb does not provide the rename Database command, it provides the rename Collection command, which not only modifies the collection name, but also modifies the database name.

db.adminCommand({renameCollection: "db1.test1", to: "db2.test2"})

This command only modifies the metadata, the cost is very small, we only need to traverse all the collections under db1, renamed to db2 to achieve rename Database name.
you can do it in this Js script

var source = "source";
var dest = "dest";
var colls = db.getSiblingDB(source).getCollectionNames();
for (var i = 0; i < colls.length; i++) {
var from = source + "." + colls[i];
var to = dest + "." + colls[i];
db.adminCommand({renameCollection: from, to: to});
}