stringqb/src/drivers/sqlite.rs

//! Database Driver for SQLite
//!
//! Use of this driver requires enabling the `sqlite` feature.
//!
//! Uses the [rusqlite](https://crates.io/crates/rusqlite) crate for
//! interfacing with the database
use super::*;

use slite::NO_PARAMS;
use slite::{params, Connection, Result as SResult};
use std::cell::RefCell;

/// The struct implementing the `DatabaseDriver` trait
#[derive(Debug)]
pub struct SQLiteDriver {
    connection: RefCell<Option<Connection>>,
}

impl SQLiteDriver {
    /// Create an SQLiteDriver driver
    pub fn new(dsn: &str) -> Self {
        let mut driver = SQLiteDriver {
            connection: RefCell::new(None),
        };

        driver.connect(dsn);

        driver
    }

    fn connect(&mut self, dsn: &str) {
        let connection = if dsn == ":memory:" {
            Connection::open_in_memory().unwrap()
        } else {
            Connection::open(dsn).unwrap()
        };

        self.connection = RefCell::new(Some(connection));
    }
}

impl DatabaseDriver for SQLiteDriver {
    fn query(&self, sql: &str) -> Result<Box<dyn Any>, Box<dyn Any>> {
        if self.connection.borrow().is_none() {
            panic!("No database connection.");
        }

        self.connection
            .borrow_mut()
            .as_mut()
            .unwrap()
            .execute(sql, NO_PARAMS);

        // TODO: map native result to generic result
        unimplemented!();
    }

    /// Return the sql to empty a table
    fn truncate(&self, table: &str) -> String {
        String::from("DELETE FROM ")
            + &self.quote_identifier(table)
    }

    fn explain(&self, sql: &str) -> String {
        format!("EXPLAIN QUERY PLAN {}", sql)
    }

    fn random(&self) -> String {
        String::from(" RANDOM()")
    }
}