CODEWITHSUNDEEP
javascriptmongodb
uttam rao
uttam rao

Reputation: 61

Make a script to create MongoDB collections from Mongo shell?

Could you please help me out in writing Mongo Shell script to create new collections and indexes to it. Here are some part of the code which i wrote and i need to refactored it.

db.createCollection("Dog", { autoIndexId : true});

db.createCollection("Cat", { autoIndexId : true});

db.createCollection("Mouse", { autoIndexId : true});

db.createCollection("Name", { autoIndexId : true});

In above code can i write single statement to create multiple collections? and also add multiple indexes to one collection in one go?

Upvotes: 2

Views: 8435

Answers (4)

prasad_
prasad_

Reputation: 14317

Create a file called as "my_scripts.js", with the following commands. This JavaScript defines the data and commands to create two collections (dogs and cats), their data (documents as JSON) and the indexes (indexes are created on the name field of the collection).

my_scripts.js:

let dogDocs = [
  {
    name: "pooch",
    breed: "poodle",
    weight: "6 lbs"
  },
  {
    name: "mutt",
    breed: "bulldog",
    weight: "10 lbs"
  }
];

let catDocs = [
  {
    name: "minni", 
    breed: "persian",
    color: "white"
  },
  {
    name: "tinkle",
    breed: "bombay",
    color: "black"
  }
];

let dogIndex = { name : 1 };
let catIndex = { name : 1 };

let collInfoObjs = [ 
  { coll: "dogs", data: dogDocs, index: dogIndex }, 
  { coll: "cats", data: catDocs, index: catIndex } 
];

for (obj of collInfoObjs) {
    db[obj.coll].insertMany(obj.data);
    db[obj.coll].createIndex(obj.index);
}


Run the script file:

From the mongo shell run the script as (you can specify the file path with the load command):

mongo > load("my_script.js");

After the script is run, you can use the following commands individually to verify the collections, their documents and the indexes:

db.dogs.find();
db.cats.find();
db.dogs.getIndexes();
db.cats.getIndexes();

Note that the documents will have a unique _id field (of type ObjectId) created if you don't supply the _id in the input JSON data.

Upvotes: 5

Joe Drumgoole
Joe Drumgoole

Reputation: 1348

We have a whole page on writing scripts for the shell. Scripts that are executed from a file use a slightly different syntax for creating connections and getting databases e.g.:

Opening connections:

new Mongo()
new Mongo(<host>)
new Mongo(<host:port>)

Getting a database:

conn = new Mongo();
db = conn.getDB("myDatabase");

Upvotes: -1

Mika Feiler
Mika Feiler

Reputation: 516

Mongo Shell scripts are just JavaScript scripts. You can use regular JavaScript control structures like loops, and string interpolation / string manipulation operations for generating collection names.

I'm guessing it will be

["Dog", "Cat", "Mouse", "Name"].forEach(function(collName) {
    db.createCollection(collName, {autoIndexId: true});
});

Upvotes: 0

prasad_
prasad_

Reputation: 14317

From the Mongo shell:

> use myNewDB;

> var myCollections = [ "Dog", "Cat", "Mouse", "Name" ];
> myCollections.forEach( collName => db.createCollection( collName, { autoIndexId : true} ) );

// -or-

> [ "Dog", "Cat", "Mouse", "Name" ].forEach( collName => db.createCollection( collName ) );

> show collections
Cat
Dog
Mouse
Name


NOTE:

{ autoIndexId : true} option is deprecated since MongoDB version 3.2; it is about creating index on _id field. The _id's unique index is mandatory now and is created automatically. So you don't have to specify the option (and cannot specify false option; it will give an error).

You can create a detailed script to add indexes after a collection is created, further. See Write scripts from Mongo Shell.

Upvotes: 0

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