Delete everything in a MongoDB database

Question

I'm doing development on MongoDB. For totally non-evil purposes, I sometimes want to blow away everything in a database—that is, to delete every single collection, and whatever else might be lying around, and start from scratch. Is there a single line of code that will let me do this? Bonus points for giving both a MongoDB console method and a MongoDB Ruby driver method.

Answer 1

In the mongo shell:

use [database]; db.dropDatabase(); 

And to remove the users:

db.dropAllUsers(); 

Answer 2

Also, from the command line:

mongo DATABASE_NAME --eval "db.dropDatabase();"

Answer 3

I had the same problem, when I needed to reset all the collections but didn't want to loose any database users. Use the following line of code, if you would like to save the user configuration for the database:

use <whichever database>
db.getCollectionNames().forEach(function(c) { if (c.indexOf("system.") == -1) db[c].drop(); })

This code will go through all collection names from one database and drop those which do not start with "system.".

Answer 4

I followed the db.dropDatabase() route for a long time, however if you're trying to use this for wiping the database in between test cases you may eventually find problems with index constraints not being honored after the database drop. As a result, you'll either need to mess about with ensureIndexes, or a simpler route would be avoiding the dropDatabase alltogether and just removing from each collection in a loop such as:

db.getCollectionNames().forEach(
  function(collection_name) {
    db[collection_name].remove()
  }
);

In my case I was running this from the command-line using:

mongo [database] --eval "db.getCollectionNames().forEach(function(n){db[n].remove()});"

Answer 5

db.getCollectionNames().forEach(c=>db[c].drop())

Answer 6

By compiling answers from @Robse and @DanH (kudos!), I've got the following solution which completely satisfies me:

db.getCollectionNames().forEach( function(collection_name) { 
  if (collection_name.indexOf("system.") == -1) 
       db[collection_name].drop();
  else  
       db[collection_name].remove({});
});

It cleans the database by dropping the user collections and emptying the system collections.

Answer 7

Here are some useful delete operations for mongodb using mongo shell

To delete particular document in collections: db.mycollection.remove( {name:"stack"} )

To delete all documents in collections: db.mycollection.remove()

To delete any particular collection : db.mycollection.drop()

to delete database : first go to that database by use mydb command and then

db.dropDatabase()

Answer 8

in case you'd need to drop everything at once: (drop all databases at once)

mongo --quiet --eval 'db.getMongo().getDBNames().forEach(function(i){db.getSiblingDB(i).dropDatabase()})'

Answer 9

Use

[databaseName]
db.Drop+databaseName();

drop collection 

use databaseName 
db.collectionName.drop();