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MongoDB Extended JSON¶
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’s internal JSON parser also recognizes the type information conveyed by the format.
- mongo Shell mode. The MongoDB’s 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.
Parsers and Supported Format¶
Input in Strict Mode¶
The following can parse representations in strict mode with recognition of the type information.
- REST Interfaces
- mongoimport
- --query option of various MongoDB tools
Other JSON parsers, including mongo shell and db.eval(), can parse strict mode representations as key/value pairs, but without recognition of the type information.
Input in mongo Shell Mode¶
The following can parse representations in mongo shell mode with recognition of the type information.
- REST Interfaces
- mongoimport
- --query option of various MongoDB tools
- mongo shell
Output in Strict mode¶
mongoexport and REST and HTTP Interfaces output data in Strict mode.
BSON Data Types and Associated Representations¶
The following presents the BSON data types and the associated representations in Strict mode and mongo Shell mode.
Binary¶
- data_binary¶
Strict Mode mongo Shell Mode { "$binary": "<bindata>", "$type": "<t>" }BinData ( <t>, <bindata> )
- <bindata> is the base64 representation of a binary string.
- <t> is the hexadecimal representation of a single byte that indicates the data type. See the extended bson documentation. http://bsonspec.org/spec.html
Date¶
- data_date¶
Strict Mode mongo Shell Mode { "$date": <date> }new Date ( <date> )
<date> is the JSON representation of a 64-bit signed integer for milliseconds since epoch UTC (unsigned before version 1.9.1).
Timestamp¶
- data_timestamp¶
Strict Mode mongo Shell Mode { "$timestamp": { "t": <t>, "i": <i> } }Timestamp( <t>, <i> )
- <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.
Regular Expression¶
- data_regex¶
Strict Mode mongo Shell Mode { "$regex": "<sRegex>", "$options": "<sOptions>" }/<jRegex>/<jOptions>
- <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.
OID¶
- data_oid¶
Strict Mode mongo Shell Mode { "$oid": "<id>" }ObjectId( "<id>" )
<id> is a 24-character hexadecimal string.
DB Reference¶
- data_ref¶
Strict Mode mongo Shell Mode { "$ref": "<name>", "$id": "<id>" }DBRef("<name>", "<id>")
- <name> is a string of valid JSON characters.
- <id> is any valid extended JSON type.
Undefined Type¶
- data_undefined¶
Strict Mode mongo Shell Mode { "$undefined": true }undefined
The representation for the JavaScript/BSON undefined type.
MinKey¶
- data_minkey¶
Strict Mode mongo Shell Mode { "$minKey": 1 }MinKey
The representation of the MinKey BSON data type that compares lower than all other types. See What is the compare order for BSON types? for more information on comparison order for BSON types.
MaxKey¶
- data_maxkey¶
Strict Mode mongo Shell Mode { "$maxKey": 1 }MaxKey
The representation of the MaxKey BSON data type that compares higher than all other types. See What is the compare order for BSON types? for more information on comparison order for BSON types.