rusql stuff

main.rs

use rusqlite::{params, Connection, Result};
use serde_derive::{Deserialize, Serialize};
use serde_rusqlite::*;
use std::fs::File;

#[derive(Debug, Deserialize, Serialize)]
struct TodoItem {
    id: Option<i32>,
    content: String,
    done: bool,
    parent_id: Option<i32>,
}

impl TodoItem {
    pub fn save(&mut self, conn: &Connection) -> Result<()> {
        Ok(match self.id {
            Some(_) => {
                conn.execute(
                    "UPDATE TodoItem
                         SET content = :content,
                             done = :done,
                         WHERE id == :id",
                    to_params_named(&self).unwrap().to_slice().as_slice(),
                )?;
            }
            None => {
                let id = conn.query_row(
                    "INSERT INTO TodoItem (content, done) VALUES (?1, ?2) RETURNING id",
                    params![self.content, self.done],
                    |row| row.get(0),
                )?;
                self.id = id;
            }
        })
    }

    pub fn get_by_id(conn: &Connection, id: i32) -> Result<Self> {
        let mut stmt = conn.prepare("SELECT * FROM TodoItem WHERE id=?1")?;
        let mut rows = stmt.query_and_then(params![id], from_row::<TodoItem>)?;
        rows.next()
            .unwrap()
            .map_err(|_| rusqlite::Error::InvalidQuery)
    }
}

fn init_db(conn: &Connection) -> Result<()> {
    conn.execute(
        "CREATE TABLE TodoItem (
                  id              INTEGER PRIMARY KEY,
                  content         TEXT NOT NULL,
                  done            BOOL,
                  parent_id       INTEGER REFERENCES TodoItem
                  )",
        [],
    )?;
    Ok(())
}

fn main() -> Result<()> {
    let conn: Connection;
    match File::open("test.sqlite") {
        Ok(_) => {
            conn = Connection::open("test.sqlite")?;
        }
        Err(_) => {
            conn = Connection::open("test.sqlite")?;
            init_db(&conn)?;
        }
    }

    let mut task1 = TodoItem {
        id: None,
        content: "Task one".to_owned(),
        done: false,
    };
    println!("{:?}", task1);
    task1.save(&conn)?;
    println!("{:?}", task1);

    let mut stmt = conn.prepare("SELECT * FROM TodoItem")?;
    let todo_iter = from_rows::<TodoItem>(stmt.query([])?);

    for person in todo_iter {
        println!("Found todo {:?}", person.unwrap());
    }
    println!("get id=12: {:?}", TodoItem::get_by_id(&conn, 12)?);
    Ok(())
}