MongoDB: Part II

use mongodb::{options::ClientOptions, Client};
use mongodb::bson::{self, doc, Bson};
use std::error::Error;
use tokio;
#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>>  {
    mongodb_init(3)?; // Needed for this playground to work
    let client_uri = "mongodb://127.0.0.1:27017/?directConnection=true";
    let mut client_options = ClientOptions::parse(&client_uri).await?;
    client_options.app_name = Some("Rust Demo".to_string());
    let client = mongodb::Client::with_options(client_options)?;
    let new_doc = doc! {
        "name": "John Doe",
        "birth": 1985,
        "salary": 36000.0,
    };
    let employees = client.database("company_database").collection("employees");
    
    let insert_result = employees.insert_one(new_doc.clone(), None).await?;
    let new_doc_id = insert_result.inserted_id;
    // Update the document:
    let update_result = employees.update_one(
        doc! {
            "_id": &new_doc_id
        },
        doc! {
            "$set": { "salary": 38000.0 }
        },
        None,
        ).await?;
    println!("Updated {} document", update_result.modified_count);
    
    let employee = employees.find_one(
            doc! {
                "name": "John Doe"
            },
            None,
        )
        .await?
        .expect("Missing document.");
    println!("Employee's salary: {}", employee.get_f64("salary")?);
    
    Ok(())
}