databend-driver

Build

cd bindings/nodejs
pnpm install
pnpm run build

Usage

const { Client } = require("databend-driver");

const client = new Client(
  "databend://root:root@localhost:8000/?sslmode=disable",
);
const conn = await client.getConn();

await conn.exec(`CREATE TABLE test (
	i64 Int64,
	u64 UInt64,
	f64 Float64,
	s   String,
	s2  String,
	d   Date,
	t   DateTime
);`);

// get rows of value array
const rows = await conn.queryIter("SELECT * FROM test");
let row = await rows.next();
while (row) {
  console.log(row.values());
  row = await rows.next();
}

// get rows of map
const rows = await conn.queryIter("SELECT * FROM test");
let row = await rows.next();
while (row) {
  console.log(row.data());
  row = await rows.next();
}

// iter rows
const rows = await conn.queryIter("SELECT * FROM test");
for await (const row of rows) {
  console.log(row.values());
}

// pipe rows
import { Transform } from "node:stream";
import { finished, pipeline } from "node:stream/promises";

const rows = await conn.queryIter("SELECT * FROM test");
const stream = rows.stream();
const transformer = new Transform({
  readableObjectMode: true,
  writableObjectMode: true,
  transform(row, _, callback) {
    console.log(row.data());
  },
});
await pipeline(stream, transformer);
await finished(stream);

Type Mapping

Databend Types

General Data Types

Databend	Node.js
BOOLEAN	Boolean
TINYINT	Number
SMALLINT	Number
INT	Number
BIGINT	BigInt
FLOAT	Number
DOUBLE	Number
DECIMAL	String
DATE	Date
TIMESTAMP	Date
VARCHAR	String
BINARY	Buffer

Semi-Structured Data Types

Databend	Node.js
ARRAY	Array
TUPLE	Array
MAP	Object
VARIANT	String / Object
BITMAP	String
GEOMETRY	String
GEOGRAPHY	String

Note: VARIANT is a json encoded string. Example:

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

const row = await conn.queryRow("SELECT * FROM example limit 1;");
const data = row.values()[0];
const value = JSON.parse(data);
console.log(value);

We also provide a helper function to convert VARIANT to Object:

const row = await conn.queryRow("SELECT * FROM example limit 1;");
row.setOpts({ variantAsObject: true });
console.log(row.data());

Development

cd bindings/nodejs
pnpm install
pnpm run build:debug
pnpm run test