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MongoDB Create Collection

In MongoDB, db.createCollection(name, options) is used to create collection. But usually you don?t need to create collection. MongoDB creates collection automatically when you insert some documents. It will be explained later. First see how to create collection:

Syntax:

Here,

Name: is a string type, specifies the name of the collection to be created.

Options: is a document type, specifies the memory size and indexing of the collection. It is an optional parameter.

Following is the list of options that can be used.

Field Type Description
Capped Boolean (Optional) If it is set to true, enables a capped collection. Capped collection is a fixed size collecction that automatically overwrites its oldest entries when it reaches its maximum size. If you specify true, you need to specify size parameter also.
AutoIndexID Boolean (Optional) If it is set to true, automatically create index on ID field. Its default value is false.
Size Number (Optional) It specifies a maximum size in bytes for a capped collection. Ifcapped is true, then you need to specify this field also.
Max Number (Optional) It specifies the maximum number of documents allowed in the capped collection.

Let's take an example to create collection. In this example, we are going to create a collection name SSSIT.

switched to db test
{ "ok" : 1 }

To check the created collection, use the command "show collections".

SSSIT

How does MongoDB create collection automatically

MongoDB creates collections automatically when you insert some documents. For example: Insert a document named seomount into a collection named SSSIT. The operation will create the collection if the collection does not currently exist.

If you want to see the inserted document, use the find() command.

Syntax:

db.collection_name.find()




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