rust connect sql server database

Cargo.toml add deps

deadpool-tiberius = {version = "0.1.8", features = ["all"]}
dotenv = "0.15.0"

.env file

DB_HOST="localhost"
DB_USER="ss"
DB_PASSWORD="Z@dd"
DB_NAME="rr"

main.rs

fn main(){
 // Get the values
    dotenv::dotenv().ok();

    let db_host = env::var("DB_HOST").expect("DB_HOST must be set");
    let db_user = env::var("DB_USER").expect("DB_USER must be set");
    let db_password = env::var("DB_PASSWORD").expect("DB_PASSWORD must be set");
    let db_name = env::var("DB_NAME").expect("DB_NAME must be set");
    let pool = deadpool_tiberius::Manager::new()
        .host(db_host)
        .port(1433)
        .basic_authentication(db_user, db_password)
        .database(db_name)
        .max_size(20)
        .trust_cert()
        .wait_timeout(1.52)
        .pre_recycle_sync(|_client: &mut Client, _metrics: &Metrics| Ok(()))
        .create_pool()
        .unwrap();
}