databend-driver 0.18.0

Databend Driver Python Binding

databend-driver

Build

cd bindings/python
maturin develop

Usage

Blocking

from databend_driver import BlockingDatabendClient

client = BlockingDatabendClient('databend+http://root:root@localhost:8000/?sslmode=disable')
conn = client.get_conn()
conn.exec(
    """
    CREATE TABLE test (
        i64 Int64,
        u64 UInt64,
        f64 Float64,
        s   String,
        s2  String,
        d   Date,
        t   DateTime
    )
    """
)
rows = conn.query_iter("SELECT * FROM test")
for row in rows:
    print(row.values())

Asyncio

import asyncio
from databend_driver import AsyncDatabendClient

async def main():
    client = AsyncDatabendClient('databend+http://root:root@localhost:8000/?sslmode=disable')
    conn = await client.get_conn()
    await conn.exec(
        """
        CREATE TABLE test (
            i64 Int64,
            u64 UInt64,
            f64 Float64,
            s   String,
            s2  String,
            d   Date,
            t   DateTime
        )
        """
    )
    rows = await conn.query_iter("SELECT * FROM test")
    async for row in rows:
        print(row.values())

asyncio.run(main())

Type Mapping

Databend Types

General Data Types

Databend	Python
BOOLEAN	bool
TINYINT	int
SMALLINT	int
INT	int
BIGINT	int
FLOAT	float
DOUBLE	float
DECIMAL	decimal.Decimal
DATE	datetime.date
TIMESTAMP	datetime.datetime
VARCHAR	str
BINARY	bytes

Semi-Structured Data Types

Databend	Python
ARRAY	list
TUPLE	tuple
MAP	dict
VARIANT	str
BITMAP	str
GEOMETRY	str

Note: VARIANT is a json encoded string. Example:

CREATE TABLE example (
    data VARIANT
);
INSERT INTO example VALUES ('{"a": 1, "b": "hello"}');

row = await conn.query_row("SELECT * FROM example limit 1;")
data = row.values()[0]
value = json.loads(data)
print(value)

APIs

AsyncDatabendClient

class AsyncDatabendClient:
    def __init__(self, dsn: str): ...
    async def get_conn(self) -> AsyncDatabendConnection: ...

AsyncDatabendConnection

class AsyncDatabendConnection:
    async def info(self) -> ConnectionInfo: ...
    async def version(self) -> str: ...
    async def exec(self, sql: str) -> int: ...
    async def query_row(self, sql: str) -> Row: ...
    async def query_iter(self, sql: str) -> RowIterator: ...
    async def stream_load(self, sql: str, data: list[list[str]]) -> ServerStats: ...

BlockingDatabendClient

class BlockingDatabendClient:
    def __init__(self, dsn: str): ...
    def get_conn(self) -> BlockingDatabendConnection: ...

BlockingDatabendConnection

class BlockingDatabendConnection:
    def info(self) -> ConnectionInfo: ...
    def version(self) -> str: ...
    def exec(self, sql: str) -> int: ...
    def query_row(self, sql: str) -> Row: ...
    def query_iter(self, sql: str) -> RowIterator: ...
    def stream_load(self, sql: str, data: list[list[str]]) -> ServerStats: ...

Row

class Row:
    def values(self) -> tuple: ...

RowIterator

class RowIterator:
    def schema(self) -> Schema: ...

    def __iter__(self) -> RowIterator: ...
    def __next__(self) -> Row: ...

    def __aiter__(self) -> RowIterator: ...
    async def __anext__(self) -> Row: ...

Field

class Field:
    @property
    def name(self) -> str: ...
    @property
    def data_type(self) -> str: ...

Schema

class Schema:
    def fields(self) -> list[Field]: ...

ServerStats

class ServerStats:
    @property
    def total_rows(self) -> int: ...
    @property
    def total_bytes(self) -> int: ...
    @property
    def read_rows(self) -> int: ...
    @property
    def read_bytes(self) -> int: ...
    @property
    def write_rows(self) -> int: ...
    @property
    def write_bytes(self) -> int: ...
    @property
    def running_time_ms(self) -> float: ...

ConnectionInfo

class ConnectionInfo:
    @property
    def handler(self) -> str: ...
    @property
    def host(self) -> str: ...
    @property
    def port(self) -> int: ...
    @property
    def user(self) -> str: ...
    @property
    def database(self) -> str | None: ...
    @property
    def warehouse(self) -> str | None: ...

Development

cd tests
make up

cd bindings/python
pipenv install --dev
pipenv run maturin develop
pipenv run behave tests/*