Custom _id Values
While MongoDB automatically generates ObjectId values for the _id field if one is not provided, we can also specify custom _id values during document insertion. This allows us to use other data types such as strings, integers, or even other objects as _id values.
Example of Specifying a Custom _id
db.users.insertOne({ _id: "user123", name: "John Doe", age: 30 })
In this example, we’re inserting a new document into the users collection with a custom _id value of “user123”.
Output:
{ "_id" : "user123", "name" : "John Doe", "age" : 30 }
How is id Generated in MongoDB
In MongoDB, each document stored in a collection is uniquely identified by a field called _id. This _id field serves as the primary key for the document and is important for ensuring document uniqueness and efficient retrieval. But have you ever wondered how these _id values are generated in MongoDB?
In this article, we’ll explore the Complexities of MongoDB ID generation by covering concepts, and examples to provide a comprehensive understanding.