The MongoDB\BSON\ObjectId class
(mongodb >=1.0.0)
简介
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 3-byte machine identifier,
- a 2-byte process ID, 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 driver 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.
类摘要
final
MongoDB\BSON\ObjectId
implements MongoDB\BSON\ObjectIdInterface
, MongoDB\BSON\Type
, Serializable
, JsonSerializable {
/* 方法 */
}
更新日志
| 版本 | 说明 |
|---|---|
| 1.3.0 | Renamed from MongoDB\BSON\ObjectID to MongoDB\BSON\ObjectId. |
| 1.2.0 | Implements Serializable and JsonSerializable. |
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::serialize — Serialize an ObjectId
- MongoDB\BSON\ObjectId::__toString — Returns the hexidecimal representation of this ObjectId
- MongoDB\BSON\ObjectId::unserialize — Unserialize an ObjectId
