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ObjectID Generator

Generate MongoDB ObjectID with optional custom timestamp

What is MongoDB ObjectID?

ObjectID Fundamentals

MongoDB ObjectID is a 12-byte unique identifier that serves as the default primary key for documents in MongoDB databases. This powerful identifier not only ensures global uniqueness but also embeds timestamp information, allowing developers to easily track document creation times.

  • •12-byte structure: Timestamp (4 bytes) + Random value (5 bytes) + Counter (3 bytes)
  • •Global uniqueness: Ensures identifier uniqueness across distributed systems
  • •Embedded timestamp: Document creation time can be extracted directly from ObjectID
  • •Hexadecimal representation: Displayed as 24-character hexadecimal string

Use Cases

  • •MongoDB Development: Generate unique primary key identifiers for new documents
  • •Data Migration: Create test data during database migration processes
  • •API Development: Generate unique resource identifiers for RESTful APIs
  • •Temporal Analysis: Extract and analyze creation timestamps from existing ObjectIDs

Frequently Asked Questions

How does ObjectID ensure uniqueness?
ObjectID ensures uniqueness by combining timestamp, machine identifier, process ID, and an incrementing counter. Even if multiple ObjectIDs are generated on the same machine within the same millisecond, the incrementing counter ensures their uniqueness.
What information can be extracted from an ObjectID?
Primarily, you can extract the document's creation timestamp. The first 8 characters of an ObjectID represent the Unix timestamp (in seconds) when it was created. Other parts contain machine/process identifiers and counter information, but these are typically not used for direct analysis.
Why use custom timestamps?
Custom timestamps are useful for data migration, test data generation, or when you need to simulate documents created at specific times. This allows developers to create ObjectIDs that appear to have been created at past or future time points.

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Pro Tip

In MongoDB queries, you can use the timestamp portion of ObjectID for time-range queries, which is more efficient than using a separate creation time field.