BSON: Difference between revisions
m {{Data Exchange}} |
→Data types and syntax: "Binary Integer Decimal (BID): MongoDB uses this binary encoding for the coefficient as specified in IEEE 754-2008. The byte order is little-endian, like the rest of the BSON types." |
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==Data types and syntax== |
==Data types and syntax== |
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BSON documents (objects) consist of an ordered list of ''elements''. |
BSON documents (objects) consist of an ordered list of ''elements''.<ref>bsonspec.org/spec.html</ref> |
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www.informit.com/articles/article.aspx?p=2247310&seqNum=4 api.mongodb.com/python/current/api/bson/regex.html MongoDB uses Perl compatible regular expressions (i.e. “PCRE” ) version 8.41 with UTF-8 support |
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Each element consists of a field name, a type, and a value. Field names are strings. Types include: |
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* string |
* string |
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* integer (32- or 64-bit) |
* integer (32- or 64-bit) |
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* double (64-bit [[IEEE 754]] floating point number) |
* double (64-bit [[IEEE 754]] floating point number) |
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* decimal128 (128-bit [[IEEE 754]] floating point number), suitable as a carrier for arbitrary precision numerics |
* decimal128 (128-bit [[IEEE 754-2008]] floating point number; Binary Integer Decimal (BID) variant), suitable as a carrier for arbitrary precision numerics with 34 decimal digits of precision, a max value of approximately 10<sup>6145</sup> |
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* date (integer number of milliseconds since the [[Unix epoch]]) |
* date (integer number of milliseconds since the [[Unix epoch]]) |
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* byte array (binary data) |
* byte array (binary data) |
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* JavaScript code |
* JavaScript code |
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* MD5 binary data |
* MD5 binary data |
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* Regular expression (Perl compatible regular expressions ("[[PCRE]]") version 8.41 with UTF-8 support, e.g. not fully Python compatible)<ref>api.mongodb.com/python/current/api/bson/regex.html</ref> |
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* Regular expression |
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* MD5 binary data |
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BSON types are nominally a superset of [[JSON]] types (JSON does not have a date or a byte array type, for example<ref name="json">[http://www.json.org/ JSON Specification]</ref>), with one exception of not having a universal "number" type as JSON does. |
BSON types are nominally a superset of [[JSON]] types (JSON does not have a date or a byte array type, for example<ref name="json">[http://www.json.org/ JSON Specification]</ref>), with one exception of not having a universal "number" type as JSON does. |
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Revision as of 11:20, 17 January 2018
| Filename extension |
.bson |
|---|---|
| Internet media type |
none[1] |
| Type of format | Data interchange |
| Extended from | JSON |
| Standard | no RFC yet |
| Website | bsonspec |
BSON /ˈbiːsən/ is a computer data interchange format used mainly as a data storage and network transfer format in the MongoDB database. It is a binary form for representing simple data structures, associative arrays (called objects or documents in MongoDB), and various data types of specific interest to MongoDB. The name "BSON" is based on the term JSON and stands for "Binary JSON".[2]
Data types and syntax
BSON documents (objects) consist of an ordered list of elements.[3]
www.informit.com/articles/article.aspx?p=2247310&seqNum=4 api.mongodb.com/python/current/api/bson/regex.html MongoDB uses Perl compatible regular expressions (i.e. “PCRE” ) version 8.41 with UTF-8 support
Each element consists of a field name, a type, and a value. Field names are strings. Types include:
- string
- integer (32- or 64-bit)
- double (64-bit IEEE 754 floating point number)
- decimal128 (128-bit IEEE 754-2008 floating point number; Binary Integer Decimal (BID) variant), suitable as a carrier for arbitrary precision numerics with 34 decimal digits of precision, a max value of approximately 106145
- date (integer number of milliseconds since the Unix epoch)
- byte array (binary data)
- boolean (
trueandfalse) - null
- BSON object
- BSON array
- JavaScript code
- MD5 binary data
- Regular expression (Perl compatible regular expressions ("PCRE") version 8.41 with UTF-8 support, e.g. not fully Python compatible)[4]
- MD5 binary data
BSON types are nominally a superset of JSON types (JSON does not have a date or a byte array type, for example[5]), with one exception of not having a universal "number" type as JSON does.
Efficiency
Compared to JSON, BSON is designed to be efficient both in storage space and scan-speed. Large elements in a BSON document are prefixed with a length field to facilitate scanning. In some cases, BSON will use more space than JSON due to the length prefixes and explicit array indices.[2]
Example
A document such as {"hello":"world"} will be stored as:
Bson:
\x16\x00\x00\x00 // total document size
\x02 // 0x02 = type String
hello\x00 // field name
\x06\x00\x00\x00world\x00 // field value (size of value, value, null terminator)
\x00 // 0x00 = type EOO ('end of object')
See also
- Comparison of data serialization formats
- JSON
- CBOR
- Smile (binary JSON)
- UBJSON
- Protocol Buffers
- Action Message Format
- Apache Thrift
- MessagePack
- Document-oriented database
- Abstract Syntax Notation One (ASN.1)
- Wireless Binary XML (WBXML)
- Efficient XML Interchange
- Sereal
References
- ^ MIME Media Types - The Internet Assigned Numbers Authority
- ^ a b BSON Specification
- ^ bsonspec.org/spec.html
- ^ api.mongodb.com/python/current/api/bson/regex.html
- ^ JSON Specification