Createcollection ()() Method in Mongodb: Create Collection in

CreateCollection () method in MongoDB

Method db.createCollection (name, options) in MongoDB helps create Collection.

Syntax

The basic syntax of createCollection () in MongoDB is as follows:

 db . createCollection ( name , options ) 

In the above command, name is the name of Collection . Options are a Document and help determine the configuration for Collection.

ParametersType Description Name String Name of Collection Options Document Define options for memory size and indexing

The options parameter is optional, so you only need to specify the name of the Collection. Here is a list of options you can use:

FieldType Descriptioncapped Boolean If true, activate a Capped Collection. This is a fixed-size Collection that automatically overrides the oldest entries when it approaches the maximum size. If you specify true, then you also need to specify the size parameter autoIndexID Boolean (Optional) If true, automatically create an index on the _id fields. The default value is false size Number (Optional) Specifies the maximum size (byte value) for a Capped Collection. If the capped parameter is true, then you also need to specify this field max Number (Optional) Determine the maximum number of Document allowed in a Capped Colleciton

While performing data insertion into the Document, MongoDB first checks the size field of Capped Collection, then checks the max field.

For instance,

The basic syntax of createCollection () method without options is as follows:

 > use test switched to db test > db . createCollection ( "mycollection" ) { "ok" : 1 } > 

You can check the created Collection using the following show collections command :

 > show collections mycollection system . indexes 

The following examples illustrate the syntax of createCollection () method with some important options.

 > db . createCollection ( "mycol" , { capped : true , autoIndexID : true , size : 6142800 , max : 10000 } ) { "ok" : 1 } > 

In MongoDB, you don't need to create Collection. MongoDB creates collections automatically, when you insert some documents.

 > db . tutorialspoint . insert ({ "name" : "tutorialspoint" }) > show collections mycol mycollection system . indexes tutorialspoint >