MongoDB db.createCollection(name, options) is used to create collection.
The following command shows how to create a collection with createCollection()
command.
db.createCollection(name, options)
name is name of collection.
Options, which is Optional, is a document and used to set up the collection.
The following table shows the list of options we can use:
| Field | Type | Description |
|---|---|---|
| capped | Boolean | Optional. true value enables a capped collection.
Capped collection is a fix-sized collection that
overwrites its oldest entries when it reaches its maximum size.
true value requires you to specify size parameter. |
| autoIndexID | Boolean | Optional, true value creates index on _id field. Default value is false. |
| size | number | Optional. Set a maximum size in bytes for a capped collection. |
| max | number | Optional. Set the maximum number of documents allowed in the capped collection. |
The following code creates a collection with default settings.
>use test switched to db test >db.createCollection("mycollection") { "ok" : 1 } >
To check the created collection, use the following command:
>show collections mycollection system.indexes
The following example shows how to use createCollection() method with options:
>db.createCollection("mycol", { capped : true, autoIndexID : true, size : 2800, max : 10000 } ) { "ok" : 1 } >
MongoDB can create collection automatically when inserting some document.
>db.tutorialspoint.insert({"name" : "java2s"})
>show collections
mycol
mycollection
system.indexes
java2s
>