diesel-selectable-macro

在插入时，Diesel允许你派生Insertable特性，通过名称插入键

use diesel::prelude::*;

#[derive(Insertable)]
#[diesel(table_name = users)]
struct User {
  email: String,
  password_hash: String,
  // There's another field, `phone`, but we are not writing it.
}

// later on...

fn write(user: User) -> QueryResult<usize> {
  diesel::insert_into(users::table).values(user).execute(conn)
}

这个crate提供了一个类似的派生特性用于读取数据。Diesel的Queryable特性通过位置而不是字段名来读取，但有时字段名更方便

use diesel::prelude::*;
use diesel_selectable_macro::Selectable;

#[derive(Queryable, Selectable)]
#[diesel(table_name = users)]
struct User {
  email: String,
  password_hash: String,
  // There's another field, `phone`, but we do not need to read it.
}

// later on...

fn read(email: String) -> QueryResult<User> {
  User::select().filter(crate::schema::users::email.eq(&email)).get_result(conn)
}

自动派生的select方法向Diesel提供了显式的字段，对应于结构体字段。