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What does ObjectId mean in MongoDB?
An ObjectID is a 12-byte Field Of BSON type. The first 4 bytes representing the Unix Timestamp of the document. The next 3 bytes are the machine Id on which the MongoDB server is running. The next 2 bytes are of process id. The last Field is 3 bytes used for increment the objectid.
Is MongoDB ID a string?
Yes, you can use a string as your _id. I’d recommend it only if you have some value (in the document) that naturally is a good unique key.
What is the structure of ObjectId in MongoDB?
An ObjectId in MongoDB is a 12-byte BSON type. In the 12-byte structure, the first 4 bytes of the ObjectId represent the time in seconds since the UNIX epoch. The next 3 bytes of the ObjectId represent the machine identifier. The next 2 bytes of the ObjectId represent the process ID.
What is MongoDB BSON ObjectId?
The MongoDB\BSON\ObjectId class ¶ 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 5-byte random number unique to a machine and process, and. a 3-byte counter, starting with a random value …
Should I use MongoDB ObjectID?
Is it ok to use Mongo’s “Object ID” as its unique identifier? Yes, it is intended for this purpose. Making unique IDs can be a pain in sharded environments, so MongoDB does this for you.
How is MongoDB _id generated?
Benefits. ObjectID is automatically generated by the database drivers, and will be assigned to the _id field of each document. ObjectID can be considered globally unique for all practical purposes. ObjectID encodes the timestamp of its creation time, which may be used for queries or to sort by creation time.
Can we rename _id in MongoDB?
Finally, keep in mind that the _id field is immutable — that is, once a document exists in your MongoDB system, it has, by definition, been assigned an _id, and you cannot change its primary key. That said, _id can be overridden when you insert new documents, but by default it will be populated with an ObjectID.
Why does MongoDB use BSON?
MongoDB represents JSON documents in binary-encoded format called BSON behind the scenes. BSON extends the JSON model to provide additional data types and to be efficient for encoding and decoding within different languages.
How does the objectId function in MongoDB work?
ObjectId () has the following attribute and methods: Returns the hexadecimal string representation of the object. Returns the timestamp portion of the object as a Date. Returns the JavaScript representation in the form of a string literal “ObjectId (…)”. Returns the representation of the object as a hexadecimal string.
What is the objectId of the BSON format?
While the BSON format itself is little-endian, the timestamp and counter values are big-endian, with the most significant bytes appearing first in the byte sequence. ObjectId () can accept the following parameter: Optional. Hexadecimal string value for the new ObjectId. ObjectId () has the following attribute and methods:
What is the 12 byte value of the objectId?
The 12-byte ObjectId value consists of: a 4-byte timestamp value, representing the ObjectId’s creation, measured in seconds since the Unix epoch While the BSON format itself is little-endian, the timestamp and counter values are big-endian, with the most significant bytes appearing first in the byte sequence.