ObjectId()
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. |
Returns the timestamp portion of the object as a Date. | |
Returns the JavaScript representation in the form of a string
literal " ObjectId(...)". | |
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