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The MongoDB\BSON\ObjectId class

(mongodb >=1.0.0)

Introduction

BSON type for an» ObjectId. The value consists of 12 bytes, where the first four bytes are a timestamp that reflect the ObjectId's creation. Specifically, the value consists of:

• a 4-byte value representing the seconds since the Unix epoch,
• a 5-byte random number unique to a machine and process, and
• a 3-byte counter, starting with a random value.

In MongoDB, each document stored in a collection requires a unique_id field that acts as a primary key. If an inserted document omits the _id field, the extension automatically generates an ObjectId for the _id field.

Using ObjectIds for the _id field provides the following additional benefits:

• The creation time of the ObjectId may be accessed using the MongoDB\BSON\ObjectId::getTimestamp() method.
• Sorting on an _id field that stores ObjectId values is roughly equivalent to sorting by creation time.

Class synopsis

Table of Contents

• MongoDB\BSON\ObjectId::__construct — Construct a new ObjectId
• MongoDB\BSON\ObjectId::getTimestamp — Returns the timestamp component of this ObjectId
• MongoDB\BSON\ObjectId::jsonSerialize — Returns a representation that can be converted to JSON
• MongoDB\BSON\ObjectId::__toString — Returns the hexidecimal representation of this ObjectId

Found A Problem?

Mike T ¶

6 years ago

Worth noting this will throw an InvalidArgumentException if string is not in the correct format