MongoDB tutorial | Learn Mongo | Create Collection in MongoDB

In this part of the Learn Mongo Series, we will learn how to create a collection in mongodb. We will be creating a collection with the name details .

In mongodb database , There are 2 methods to create a collection. We can either create it using the following command db.createCollection(name, options) or we can create it automatically by inserting the data into a document. We will learn both the methods in detail below :

Method 1 - db.createCollection(name, options) This command is used to create a collection manually. It takes 2 parameters :
- name : This is a required parameter and takes string as input.We pass collection name to be created here.
- options : This is an optional parameter which if passes can have any of the following choices :
  1. capped : It is optional. It's datatype is boolean . It can be either true or false. Capped collections are fixed size collections which automatically overrides its oldest entry after reaching its maximum size. Default value is false . If capped is true , then it is mandatory for us to give value to size param also as they are inter-dependent. Capped collections are not recommended for sensitive data.
  2. size : It is optional. It's datatype is number .It is used to specify the maximum size for a capped collection. It specifies size in bytes. If capped is true , then it is mandatory to give this parameter.
  3. max : It is optional. It's datatype is number . It is used to specify the maximum number of collection allowed in a capped collection.
  4. autoindexed : It's datatype is boolean . If true, used to create an automatic index on _id field.
```
										
> use demo_db
switched to db demo_db
> db.createCollection("details")
{ "ok" : 1 }
>
										
									
```
Let's see a collection with some parameters :
```
										
> use demo_db
switched to db demo_db
> db.createCollection("details_new",{capped : true, size : 12400, max : 10000,autoIndexId : true })
{ "ok" : 1 }
>
										
									
```
We can see the created collection using the show collections command as shown below :
```
										
> use demo_db
switched to db demo_db
> db.createCollection("details_new",{capped : true, size : 12400, max : 10000,autoIndexId : true })
{ "ok" : 1 }
>show collections
details
details_new
>
										
									
```
Method 2 - Creating collection automatically : We can create a collection automatically by just inserting the data in a mongodb document. The syntax is db.<collection_name>.insert({"key":"value"}) as shown below :
```
										
> use demo_db
switched to db demo_db
>db.students.insert({"name":"alex"})
{ "ok" : 1 }
>show collections
details
details_new
students
>
										
									
```

In this part of learn mongo series , we learned about how we can create a collection in mongodb. We learned the following commands of mongodb :

use : This command is use to either create a new database or switch to an already existing database.
db.createCollection(name,options) : This command is used to create a collection manually.
db.<collection_name>.insert({"key":"value"}) : This command is used to create the collection automatically by inserting data into the document.
show collections : This command is used to list all the mongodb collections of the current mongodb database on the console.

Day 4 : Create Collection in MongoDB