BSONEachRow - Clickhouse

Input	Output	Alias
✔	✔

Description {#description}

The BSONEachRow format parses data as a sequence of Binary JSON (BSON) documents without any separator between them. Each row is formatted as a single document and each column is formatted as a single BSON document field with the column name as a key.

Data types matching {#data-types-matching}

For output it uses the following correspondence between ClickHouse types and BSON types:

ClickHouse type	BSON Type
Bool	`\x08` boolean
Int8/UInt8/Enum8	`\x10` int32
Int16/UInt16/Enum16	`\x10` int32
Int32	`\x10` int32
UInt32	`\x12` int64
Int64/UInt64	`\x12` int64
Float32/Float64	`\x01` double
Date/Date32	`\x10` int32
DateTime	`\x12` int64
DateTime64	`\x09` datetime
Decimal32	`\x10` int32
Decimal64	`\x12` int64
Decimal128	`\x05` binary, `\x00` binary subtype, size = 16
Decimal256	`\x05` binary, `\x00` binary subtype, size = 32
Int128/UInt128	`\x05` binary, `\x00` binary subtype, size = 16
Int256/UInt256	`\x05` binary, `\x00` binary subtype, size = 32
String/FixedString	`\x05` binary, `\x00` binary subtype or \x02 string if setting output_format_bson_string_as_string is enabled
UUID	`\x05` binary, `\x04` uuid subtype, size = 16
Array	`\x04` array
Tuple	`\x04` array
Named Tuple	`\x03` document
Map	`\x03` document
IPv4	`\x10` int32
IPv6	`\x05` binary, `\x00` binary subtype

For input it uses the following correspondence between BSON types and ClickHouse types:

BSON Type	ClickHouse Type
`\x01` double	Float32/Float64
`\x02` string	String/FixedString
`\x03` document	Map/Named Tuple
`\x04` array	Array/Tuple
`\x05` binary, `\x00` binary subtype	String/FixedString/IPv6
`\x05` binary, `\x02` old binary subtype	String/FixedString
`\x05` binary, `\x03` old uuid subtype	UUID
`\x05` binary, `\x04` uuid subtype	UUID
`\x07` ObjectId	String/FixedString
`\x08` boolean	Bool
`\x09` datetime	DateTime64
`\x0A` null value	NULL
`\x0D` JavaScript code	String/FixedString
`\x0E` symbol	String/FixedString
`\x10` int32	Int32/UInt32/Decimal32/IPv4/Enum8/Enum16
`\x12` int64	Int64/UInt64/Decimal64/DateTime64

Other BSON types are not supported. Additionally, it performs conversion between different integer types. For example, it is possible to insert a BSON int32 value into ClickHouse as UInt8.

Big integers and decimals such as Int128/UInt128/Int256/UInt256/Decimal128/Decimal256 can be parsed from a BSON Binary value with the \x00 binary subtype. In this case, the format will validate that the size of the binary data equals the size of the expected value.

:::note This format does not work properly on Big-Endian platforms. :::

Example usage {#example-usage}

Inserting data {#inserting-data}

Using a BSON file with the following data, named as football.bson:

text

    ┌───────date─┬─season─┬─home_team─────────────┬─away_team───────────┬─home_team_goals─┬─away_team_goals─┐
 1. │ 2022-04-30 │   2021 │ Sutton United         │ Bradford City       │               1 │               4 │
 2. │ 2022-04-30 │   2021 │ Swindon Town          │ Barrow              │               2 │               1 │
 3. │ 2022-04-30 │   2021 │ Tranmere Rovers       │ Oldham Athletic     │               2 │               0 │
 4. │ 2022-05-02 │   2021 │ Port Vale             │ Newport County      │               1 │               2 │
 5. │ 2022-05-02 │   2021 │ Salford City          │ Mansfield Town      │               2 │               2 │
 6. │ 2022-05-07 │   2021 │ Barrow                │ Northampton Town    │               1 │               3 │
 7. │ 2022-05-07 │   2021 │ Bradford City         │ Carlisle United     │               2 │               0 │
 8. │ 2022-05-07 │   2021 │ Bristol Rovers        │ Scunthorpe United   │               7 │               0 │
 9. │ 2022-05-07 │   2021 │ Exeter City           │ Port Vale           │               0 │               1 │
10. │ 2022-05-07 │   2021 │ Harrogate Town A.F.C. │ Sutton United       │               0 │               2 │
11. │ 2022-05-07 │   2021 │ Hartlepool United     │ Colchester United   │               0 │               2 │
12. │ 2022-05-07 │   2021 │ Leyton Orient         │ Tranmere Rovers     │               0 │               1 │
13. │ 2022-05-07 │   2021 │ Mansfield Town        │ Forest Green Rovers │               2 │               2 │
14. │ 2022-05-07 │   2021 │ Newport County        │ Rochdale            │               0 │               2 │
15. │ 2022-05-07 │   2021 │ Oldham Athletic       │ Crawley Town        │               3 │               3 │
16. │ 2022-05-07 │   2021 │ Stevenage Borough     │ Salford City        │               4 │               2 │
17. │ 2022-05-07 │   2021 │ Walsall               │ Swindon Town        │               0 │               3 │
    └────────────┴────────┴───────────────────────┴─────────────────────┴─────────────────┴─────────────────┘

Insert the data:

sql

INSERT INTO football FROM INFILE 'football.bson' FORMAT BSONEachRow;

Reading data {#reading-data}

Read data using the BSONEachRow format:

sql

SELECT *
FROM football INTO OUTFILE 'docs_data/bson/football.bson'
FORMAT BSONEachRow

:::tip BSON is a binary format that does not display in a human-readable form on the terminal. Use the INTO OUTFILE to output BSON files. :::

Format settings {#format-settings}

Setting	Description	Default
`output_format_bson_string_as_string`	Use BSON String type instead of Binary for String columns.	`false`
`input_format_bson_skip_fields_with_unsupported_types_in_schema_inference`	Allow skipping columns with unsupported types while schema inference for format BSONEachRow.	`false`