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

    final class MongoDB\BSON\ObjectId implements MongoDB\BSON\ObjectIdInterface, MongoDB\BSON\Type, Serializable, JsonSerializable, Stringable {
    /* Methods */
    final public __construct(?string $id = null)
    final public getTimestamp(): int
    final public jsonSerialize(): mixed
    final public serialize(): string
    final public __toString(): string
    final public unserialize(string $data): void
    }

    Changelog

    Version Description
    PECL mongodb 1.12.0 Implements Stringable for PHP 8.0+.
    PECL mongodb 1.3.0

    Renamed from MongoDB\BSON\ObjectID to MongoDB\BSON\ObjectId.

    Implements MongoDB\BSON\ObjectIdInterface.

    PECL mongodb 1.2.0 Implements Serializable and JsonSerializable.

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