69 lines
1.9 KiB
Rust
69 lines
1.9 KiB
Rust
// As of Rust 1.34.0, these dependencies need to be declared in this order using
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// `extern crate` in your `main.rs` file. See
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// https://github.com/emk/rust-musl-builder/issues/69.
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extern crate openssl;
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#[macro_use]
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extern crate diesel;
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use diesel::connection::Connection;
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use diesel::pg::PgConnection;
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use diesel::prelude::*;
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use diesel::sqlite::SqliteConnection;
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use diesel::sql_types::{HasSqlType, Integer, Text};
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use std::env;
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table! {
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users (id) {
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id -> Integer,
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name -> Text,
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}
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}
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#[derive(Debug, Insertable, Queryable)]
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#[table_name="users"]
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struct User {
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id: i32,
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name: String,
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}
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/// Run a query against our `users` table.
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fn query_users<C>(conn: &C)
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where
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// OK, we made the mistake of trying to write generic `diesel` code that
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// works for multiple types of databases. This requires some pretty
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// hairy declarations.
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C: Connection,
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User: Queryable<(Integer, Text), C::Backend>,
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C::Backend: HasSqlType<Integer> + HasSqlType<Text>,
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{
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let rows = users::table
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.limit(5)
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.load::<User>(conn)
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.expect("could not load users");
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for row in rows {
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println!("{:?}", row);
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}
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}
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fn main() {
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println!("Hello, world!");
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// Only run our database example if we have a database. Otherwise, we just
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// want to make sure everything links correctly.
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if let Ok(url) = env::var("DATABASE_URL") {
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if url.starts_with("postgres:") {
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let conn = PgConnection::establish(&url)
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.expect("could not connect to database");
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query_users(&conn);
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} else if url.starts_with("sqlite:") {
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let conn = SqliteConnection::establish(&url)
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.expect("could not connect to database");
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query_users(&conn);
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} else {
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println!("Unsupported database URL: {}", url);
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}
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} else {
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println!("No DATABASE_URL set, so doing nothing")
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}
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}
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