MongoDB, the industry leader in No SQL databases, can handle a very high volume of data. In this blog, I’ll explain MongoDB create collection steps. We will also go through various other methods to create a collection in mongodb. So let’s get started.
Create collection in MongoDB
MongoDB stores data in JSON documents in mongo collections. MongoDB collections are similar to RDBS tables.
Before creating a collection, create the database first. Type the below command to create a database name naiveskill
Mongodb create database
use naiveskill
type the below command to verify the current database in which the user is:
> db
naiveskillNow it’s time to create the collection. Use mongodb createCollection command to create a collection in mongodb. The createCollection command follows the below syntax:
db.createCollection(name, options)Where
- Name: Name of the collection to be created in string format
- Options : (optional)options about memory size and indexing.
Now Type the below command a create a basic collection name test
db.createCollection('test')
Verify the test collection by typing the below command
show collections
testFantastic, Now you know how to create a basic collection in MongoDB. Next, I will be explaining to you how to create a collection in mongodb with schema.
Mongodb create collection with schema
There are numerous ways to create a collection with schema in mongodb. Still, the simplest one is by using JSON schema validator.Json schema validated, validates the data schema before inserting the record. If the document you are inserting does not adhere to the schema defined, that record will be discarded.
Let’s proceed further and create a collection name Inventory with three fields ‘brand’, ‘year’, and ‘model’.
Mongodb create collection with schema and document validation
db.createCollection('Inventory', {
validator: {
$jsonSchema: {
bsonType: 'object',
required: ['brand', 'year', 'model'],
properties: {
title: {
bsonType: 'string',
description: 'must be a string and is required'
},
brand: {
bsonType: 'string',
description: 'must be a string and is required'
},
Year: {
bsonType: 'string',
description: 'must be an string and is required'
},
model: {
bsonType: 'string',
description: 'must be an array and is required',
}
}
}
}
});If you are getting Ok in the result, it means your collection will be successfully created.
Insert Document with invalid schema in mongodb collection
Let’s insert the document into the Inventory collection by typing the below command.
db.Inventory.insertOne({brand:"iphone",model:"6s"})
The document has not been inserted into the inventory collection because the Inventory collection expects three fields, and we have just passed two fields.
Insert Document with valid schemain mongodb collection
Now let’s insert a document into the mongodb collection by specifying all the mandatory fields.
> db.Inventory.insertOne({brand:"iphone",year:"2015",model:"6s"})
{
"acknowledged" : true,
"insertedId" : ObjectId("6129f22afe4e5ef36181631a")
}
>As you can see from the above output, that data gets correctly inserted into the mongodb collection without any error.
Create collection in mongodb compass
In this session, we will learn how to insert data into a mongodb collection using a mongodb compass.
You can follow this link to download the Mongodb compass.
Open the Mongodb compass and paste the below connection string to connect to mongodb.
mongodb://localhost:27017/admin
Click on create a database to create a new database.
Now provide the database name and a collection name
Click on create a database to create the naive database and testnaive collection.
Note: While creating a mongodb collection, you have the option to select a capped collection or custom collection, or time-series collection. More details about such types of collections can be found here.
Now, Click on database naive, and it will show you all the collections under it.
Similarly, the new collection can be created by clicking on CREATE COLLECTION button.
MongoDB create collection if not exist
Sometimes we need to check if the collection already exists before creating a new one. You can use the below command to check if the collection already exists in mongodb before creating a new one.
db.getCollectionNames({name: "collection_name>"},
function(err, names) {console.log('Exists: ', names.length < 0)
});But this method is not recommended. The simplest way will be to use any programming language like python or node js to interact with MongoDB. You can follow this link to have a basic idea about how to interact with mongodb using python.
In the python client, you can type the below command to get a list of collections.
import pymongo
client = pymongo.MongoClient("mongodb://localhost:27017/")
client['database_name>'].list_collection_names()Explanation
- First, we import the pymongo client in the python shell. Please make sure you to downloaded the pymongo package before importing.
- Then in the second step, we are creating a mongo client.
- Then finally using the mongo client we are listing all collections in a particular database.
Mongodb create collection nodejs
Mongodb has many drivers using which you can interact with Mongodb, and one such driver is node.js. The MongoDB Node.js driver allows Node.js applications to connect to MongoDB and work with data.
Save the below command into a file name create_test_collection.js to create a database name naiveskill in the test database.
// import mongodb
var MongoClient = require('mongodb').MongoClient;
var url = "mongodb://localhost:27017/test";
//client connect
MongoClient.connect(url, function(err, db) {
if (err) throw err;
dbo.createCollection("naiveskill", function(err, res) {
if (err) throw err;
console.log("Collection created!");
db.close();
});
});Now run the below command using node.
node create_test_collection.js
Collection is created!Awesome, You have successfully created a collection using node.js.
Mongodb create collection python
Python is the first choice of data scientists and data engineers for language selection. This is because of the vast community support and multiple available packages.
And MongoDB, one of the most famous No SQL databases, can be used to build web applications, JSON APIs, etc.
To connect MongoDB with python, we can use the pymongo driver. It is the official driver provided by MongoDB.
Before creating a collection in mongodb, a database must be created. To create a database, a mongo client needs to be created. Once the client gets created
import pymongo
client = pymongo.MongoClient("mongodb://localhost:27017/")
db = client['naiveskill']Now type the below command to create a collection name mycollection
collection = db['myCollection']Delete a mongodb collection
Deleting a collection in mongodb is quite simple. We can use the drop() command to delete a collection in mongodb.
Type the below command to delete the Inventory collection that we created earlier
db.Inventory.drop()
trueMongodb create document
Mongodb creating documents means inserting a document in the mongodb collection. In mongodb, you have the flexibility to insert either a single document or multiple documents at once.
Mongodb insert single documents
With the mongodb insert command, we can insert a single document into the mongodb collection.
Type the below command to insert a document in the tech collection
db.tech.insert(
{
'Kind': 'Mobile',
'lang': 'iphone 6s',
'Rating': 4.2
})> db.tech.insert(
... {
... 'Kind': 'Mobile',
... 'brand': 'iphone 6s',
... 'Rating': 4.2
... })
WriteResult({ "nInserted" : 1 })Mongodb insert multiple documents
Similarly, using mongodb to insert many commands, we can insert multiple documents into the mongodb collections.
> db.tech.insertMany([
... {
... 'Kind': 'Mobile',
... 'lang': 'iphone 6s',
... 'Rating': 4.2
... },
... {
... 'Kind': 'laptop',
... 'lang': 'acer',
... 'Rating': 3.9
... },
... {
... 'Kind': 'mobile',
... 'lang': 'samsung',
... 'Rating': 4.0
... },
... ])
{
"acknowledged" : true,
"insertedIds" : [
ObjectId("60c37883a9c3d411ad96c6e7"),
ObjectId("60c37883a9c3d411ad96c6e8"),
ObjectId("60c37883a9c3d411ad96c6e9")
]
}You can follow this link to get the complete tutorial on mongodb commands.
Conclusion
Finally, we have come to the end of this basic mongodb create collection tutorial. In this tutorial, we have learned different ways to create a collection in mongodb.
I hope you have liked this tutorial. Please do let me know in the comment box if you face any issues while following along.
More to read
How to create a database in mongodb
Install MongoDB using docker
