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MongoDB Extended JSON (v1)

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  • MongoDB Extended JSON v1 and MongoDB Drivers
  • Parsers and Supported Format
  • BSON Data Types and Associated Representations
Important
Disambiguation

JSON can only represent a subset of the types supported by BSON. To preserve type information, MongoDB adds the following extensions to the JSON format:

  • Strict mode. Strict mode representations of BSON types conform to the JSON RFC. Any JSON parser can parse these strict mode representations as key/value pairs; however, only the MongoDB internal JSON parser recognizes the type information conveyed by the format.
  • mongo Shell mode. The MongoDB internal JSON parser and the mongo shell can parse this mode.

The representation used for the various data types depends on the context in which the JSON is parsed.

The following drivers use the Extended JSON v1.0 (Legacy)

  • C#
  • Ruby

For the other drivers, refer to MongoDB Extended JSON (v2).

The following can parse representations in strict mode with recognition of the type information.

Other JSON parsers, including mongo shell, can parse strict mode representations as key/value pairs, but without recognition of the type information.

The following can parse representations in mongo shell mode with recognition of the type information.

  • mongoimport version 4.0 and earlier
  • --query option of various MongoDB tools
  • mongo shell

Before version 4.2, mongoexport outputs data in Strict mode of MongoDB Extended JSON v1.

Before version 4.2, bsondump outputs in mongo Shell mode.

The following presents the BSON data types and the associated representations in Strict mode and mongo Shell mode.

data_binary
Strict Mode
mongo Shell Mode
{ "$binary": "<bindata>", "$type": "<t>" }
BinData ( <t>, <bindata> )

Where the values are as follows:

  • <bindata> is the base64 representation of a binary string.
  • <t> is a representation of a single byte indicating the data type. In Strict mode it is a hexadecimal string, and in Shell mode it is an integer. See the extended bson documentation. http://bsonspec.org/spec.html
data_date
Strict Mode
mongo Shell Mode
{ "$date": "<date>" }
new Date ( <date> )

In Strict mode, <date> is an ISO-8601 date format with a mandatory time zone field following the template YYYY-MM-DDTHH:mm:ss.mmm<+/-Offset>.

In Shell mode, <date> is the JSON representation of a 64-bit signed integer giving the number of milliseconds since epoch UTC.

data_timestamp
Strict Mode
mongo Shell Mode
{ "$timestamp": { "t": <t>, "i": <i> } }
Timestamp( <t>, <i> )

Where the values are as follows:

  • <t> is the JSON representation of a 32-bit unsigned integer for seconds since epoch.
  • <i> is a 32-bit unsigned integer for the increment.
data_regex
Strict Mode
mongo Shell Mode
{ "$regex": "<sRegex>", "$options": "<sOptions>" }
/<jRegex>/<jOptions>

Where the values are as follows:

  • <sRegex> is a string of valid JSON characters.
  • <jRegex> is a string that may contain valid JSON characters and unescaped double quote (") characters, but may not contain unescaped forward slash (/) characters.
  • <sOptions> is a string containing the regex options represented by the letters of the alphabet.
  • <jOptions> is a string that may contain only the characters 'g', 'i', 'm' and 's' (added in v1.9). Because the JavaScript and mongo Shell representations support a limited range of options, any nonconforming options will be dropped when converting to this representation.
data_oid
Strict Mode
mongo Shell Mode
{ "$oid": "<id>" }
ObjectId( "<id>" )

Where the values are as follows:

  • <id> is a 24-character hexadecimal string.
data_ref
Strict Mode
mongo Shell Mode
{ "$ref": "<name>", "$id": "<id>" }
DBRef("<name>", "<id>")

Where the values are as follows:

  • <name> is a string of valid JSON characters.
  • <id> is any valid extended JSON type.
data_undefined
Strict Mode
mongo Shell Mode
{ "$undefined": true }
undefined

The representation for the JavaScript/BSON undefined type.

You cannot use undefined in query documents. Consider the following document inserted into the people collection:

db.people.insert( { name : "Sally", age : undefined } )

The following queries return an error:

db.people.find( { age : undefined } )
db.people.find( { age : { $gte : undefined } } )

However, you can query for undefined values using $type, as in:

db.people.find( { age : { $type : 6 } } )

This query returns all documents for which the age field has value undefined.

data_minkey
Strict Mode
mongo Shell Mode
{ "$minKey": 1 }
MinKey

The representation of the MinKey BSON data type that compares lower than all other types. See Comparison/Sort Order for more information on comparison order for BSON types.

data_maxkey
Strict Mode
mongo Shell Mode
{ "$maxKey": 1 }
MaxKey

The representation of the MaxKey BSON data type that compares higher than all other types. See Comparison/Sort Order for more information on comparison order for BSON types.

data_numberlong
Strict Mode
mongo Shell Mode
{ "$numberLong": "<number>" }
NumberLong( "<number>" )

NumberLong is a 64 bit signed integer. You must include quotation marks or it will be interpreted as a floating point number, resulting in a loss of accuracy.

For example, the following commands insert 9223372036854775807 as a NumberLong with and without quotation marks around the integer value:

db.json.insert( { longQuoted : NumberLong("9223372036854775807") } )
db.json.insert( { longUnQuoted : NumberLong(9223372036854775807) } )

When you retrieve the documents, the value of longUnQuoted has changed, while longQuoted retains its accuracy:

db.json.find()
{ "_id" : ObjectId("54ee1f2d33335326d70987df"), "longQuoted" : NumberLong("9223372036854775807") }
{ "_id" : ObjectId("54ee1f7433335326d70987e0"), "longUnQuoted" : NumberLong("-9223372036854775808") }

New in version 3.4.

data_numberdecimal
Strict Mode
mongo Shell Mode
{ "$numberDecimal": "<number>" }
NumberDecimal( "<number>" )

NumberDecimal is a high-precision decimal. You must include quotation marks, or the input number will be treated as a double, resulting in data loss.

For example, the following commands insert 123.40 as a NumberDecimal with and without quotation marks around the value:

db.json.insert( { decimalQuoted : NumberDecimal("123.40") } )
db.json.insert( { decimalUnQuoted : NumberDecimal(123.40) } )

When you retrieve the documents, the value of decimalUnQuoted has changed, while decimalQuoted retains its specified precision:

db.json.find()
{ "_id" : ObjectId("596f88b7b613bb04f80a1ea9"), "decimalQuoted" : NumberDecimal("123.40") }
{ "_id" : ObjectId("596f88c9b613bb04f80a1eaa"), "decimalUnQuoted" : NumberDecimal("123.400000000000") }
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