ObjectId()

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Description
Compatibility
Syntax
Methods and Attributes
Examples

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Description

ObjectId(<hexadecimal>)

Returns a new ObjectId value. The 12-byte ObjectId value consists of:

a 4-byte timestamp value, representing the ObjectId's creation, measured in seconds since the Unix epoch
a 5-byte random value generated once per process. This random value is unique to the machine and process.
a 3-byte incrementing counter, initialized to a random value

While the BSON format itself is little-endian, the timestamp and counter values are big-endian, with the most significant bytes appearing first in the byte sequence.

Compatibility

You can use ObjectId() for deployments hosted in the following environments:

MongoDB Atlas: The fully managed service for MongoDB deployments in the cloud

MongoDB Enterprise: The subscription-based, self-managed version of MongoDB
MongoDB Community: The source-available, free-to-use, and self-managed version of MongoDB

Syntax

ObjectId() can accept one of the following inputs:

Input Type	Description
`hexadecimal`	Optional. A 24 character hexadecimal string value for the new ObjectId.
`integer`	Optional. The integer value, in seconds, is added to the Unix epoch to create the new timestamp.

Methods and Attributes

ObjectId() has the following attribute and methods:

Attribute/Method	Description
`str`	Returns the hexadecimal string representation of the object.
`ObjectId.getTimestamp()`	Returns the timestamp portion of the object as a Date.
`ObjectId.toString()`	Returns the JavaScript representation in the form of a string literal "`ObjectId(...)`".
`ObjectId.valueOf()`	Returns the representation of the object as a hexadecimal string. The returned string is the `str` attribute.

Examples

Generate a New ObjectId

To generate a new ObjectId, use ObjectId() with no argument:

x = ObjectId()

In this example, the value of x would be:

ObjectId("507f1f77bcf86cd799439011")

Specify a Hexadecimal String

To generate a new ObjectId using ObjectId() with a unique hexadecimal string:

y = ObjectId("507f191e810c19729de860ea")

In this example, the value of y would be:

ObjectId("507f191e810c19729de860ea")

Access the Hexadecimal String

Access the str attribute of an ObjectId() object, as follows:

ObjectId("507f191e810c19729de860ea").str

This operation will return the following hexadecimal string:

507f191e810c19729de860ea