databend-driver

Databend Python Client

Usage

PEP 249 Cursor Object

from databend_driver import BlockingDatabendClient

client = BlockingDatabendClient('databend://root:root@localhost:8000/?sslmode=disable')
cursor = client.cursor()

cursor.execute(
    """
    CREATE TABLE test (
        i64 Int64,
        u64 UInt64,
        f64 Float64,
        s   String,
        s2  String,
        d   Date,
        t   DateTime
    )
    """
)
cursor.execute("INSERT INTO test VALUES (?, ?, ?, ?, ?, ?, ?)", (1, 1, 1.0, 'hello', 'world', '2021-01-01', '2021-01-01 00:00:00'))
cursor.execute("SELECT * FROM test")
rows = cursor.fetchall()
for row in rows:
    print(row.values())
cursor.close()

Blocking Connection Object

from databend_driver import BlockingDatabendClient

client = BlockingDatabendClient('databend://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())
conn.close()

Asyncio Connection Object

import asyncio
from databend_driver import AsyncDatabendClient

async def main():
    client = AsyncDatabendClient('databend://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())
    await conn.close()

asyncio.run(main())

Parameter bindings

# Test with positional parameters
row = await context.conn.query_row("SELECT ?, ?, ?, ?", (3, False, 4, "55"))
row = await context.conn.query_row(
    "SELECT :a, :b, :c, :d", {"a": 3, "b": False, "c": 4, "d": "55"}
)
row = await context.conn.query_row(
    "SELECT ?", 3
)
row = await context.conn.query_row("SELECT ?, ?, ?, ?", params = (3, False, 4, "55"))

Type Mapping

Databend Types

General Data Types

Semi-Structured Data Types

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 close(self) -> None: ...
    async def exec(self, sql: str, params: list[string] | tuple[string] | any = None) -> int: ...
    async def query_row(self, sql: str, params: list[string] | tuple[string] | any = None) -> Row: ...
    async def query_iter(self, sql: str, params: list[string] | tuple[string] | any = None) -> RowIterator: ...
    async def stream_load(self, sql: str, data: list[list[str]]) -> ServerStats: ...
    async def load_file(self, sql: str, file: str, format_option: dict, copy_options: dict = None) -> ServerStats: ...

BlockingDatabendClient

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

BlockingDatabendConnection

class BlockingDatabendConnection:
    def info(self) -> ConnectionInfo: ...
    def version(self) -> str: ...
    def close(self) -> None: ...
    def exec(self, sql: str, params: list[string] | tuple[string] | any = None) -> int: ...
    def query_row(self, sql: str, params: list[string] | tuple[string] | any = None) -> Row: ...
    def query_iter(self, sql: str, params: list[string] | tuple[string] | any = None) -> RowIterator: ...
    def stream_load(self, sql: str, data: list[list[str]]) -> ServerStats: ...
    def load_file(self, sql: str, file: str, format_option: dict, copy_options: dict = None) -> ServerStats: ...

BlockingDatabendCursor

class BlockingDatabendCursor:
    @property
    def description(self) -> list[tuple[str, str, int | None, int | None, int | None, int | None, bool | None]] | None: ...
    @property
    def rowcount(self) -> int: ...
    def close(self) -> None: ...
    def execute(self, operation: str, params: list[string] | tuple[string] = None) -> None | int: ...
    def executemany(self, operation: str, params: list[string] | tuple[string] = None, values: list[list[string] | tuple[string]]) -> None | int: ...
    def fetchone(self) -> Row | None: ...
    def fetchmany(self, size: int = 1) -> list[Row]: ...
    def fetchall(self) -> list[Row]: ...

    # Optional DB API Extensions
    def next(self) -> Row: ...
    def __next__(self) -> Row: ...
    def __iter__(self) -> BlockingDatabendCursor: ...

Row

class Row:
    def values(self) -> tuple: ...
    def __len__(self) -> int: ...
    def __iter__(self) -> Row: ...
    def __next__(self) -> any: ...
    def __dict__(self) -> dict: ...
    def __getitem__(self, key: int | str) -> any: ...

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
uv sync
source .venv/bin/activate
maturin develop --uv

behave tests/asyncio
behave tests/blocking
behave tests/cursor