driver

Databend Driver

Databend unified SQL client for RestAPI and FlightSQL

usage

exec

use databend_driver::Client;

let dsn = "databend://root:@localhost:8000/default?sslmode=disable".to_string();
let client = Client::new(dsn);
let conn = client.get_conn().await.unwrap();

let sql_create = "CREATE TABLE books (
    title VARCHAR,
    author VARCHAR,
    date Date
);";
conn.exec(sql_create).await.unwrap();
let sql_insert = "INSERT INTO books VALUES ('The Little Prince', 'Antoine de Saint-Exupéry', '1943-04-06');";
conn.exec(sql_insert).await.unwrap();

query row

let row = conn.query_row("SELECT * FROM books;").await.unwrap();
let (title,author,date): (String,String,i32) = row.unwrap().try_into().unwrap();
println!("{} {} {}", title, author, date);

query iter

let mut rows = conn.query_iter("SELECT * FROM books;").await.unwrap();
while let Some(row) = rows.next().await {
    let (title,author,date): (String,String,chrono::NaiveDate) = row.unwrap().try_into().unwrap();
    println!("{} {} {}", title, author, date);
}

Type Mapping

Databend Types

General Data Types

Databend	Rust
BOOLEAN	bool
TINYINT	i8,u8
SMALLINT	i16,u16
INT	i32,u32
BIGINT	i64,u64
FLOAT	f32
DOUBLE	f64
DECIMAL	String
DATE	chrono::NaiveDate
TIMESTAMP	chrono::NaiveDateTime
VARCHAR	String
BINARY	Vec<u8>

Semi-Structured Data Types

Databend	Rust
ARRAY[T]	Vec<T>
TUPLE[T, U]	(T, U)
MAP[K, V]	HashMap<K, V>
VARIANT	String
BITMAP	String
GEOMETRY	String

Note: VARIANT is a json encoded string. Example:

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

let row = conn.query_row("SELECT * FROM example limit 1;").await.unwrap();
let (data,): (String,) = row.unwrap().try_into().unwrap();
let value: serde_json::Value = serde_json::from_str(&data).unwrap();
println!("{:?}", value);