Postgresql 使用 Postgres 在 Rust 的 Diesel 库中添加时间戳

今天我一直在关注Rust's Diesel ORM的this walk-through，但我没法得到Timestamp.

Cargo.toml

[dependencies]
diesel = { version = "0.6.2", features = ["chrono"] }
diesel_codegen = { version = "0.6.2", default-features = false, features = ["nightly", "postgres"] }
dotenv = "0.8.0"
dotenv_macros = "0.8.0"

models.rs

#[derive(Queryable)]

pub struct Author {
    pub id: i32,
    pub first_name: String,
    pub last_name: String,
    pub email: String
}

pub struct Post {
    pub id: i32,
    pub author: Author,
    pub title: String,
    pub body: String,
    pub published: bool,
    pub created: Timestamp,
    pub updated: Timestamp
}

(我读到有diesel::types::Timestamp种)

lib.rs

#![feature(custom_derive, custom_attribute, plugin)]
#![plugin(diesel_codegen, dotenv_macros)]

#[macro_use]
extern crate diesel;
extern crate dotenv;

pub mod schema;
pub mod models;

use diesel::prelude::*;
use diesel::types::Timestamp;
use diesel::pg::PgConnection;
use dotenv::dotenv;
use std::env;

pub fn establish_connection() -> PgConnection {
    dotenv().ok();

    let database_url = env::var("DATABASE_URL").
        expect("DATABASE_URL must be set");
    PgConnection::establish(&database_url).
        expect(&format!("Error connecting to {}", database_url))
}

但当我try 使用它时，我会遇到以下错误:

<diesel macros>:5:1: 5:71 note: in this expansion of table_body! (defined in <diesel macros>)
src/schema.rs:1:1: 1:40 note: in this expansion of table! (defined in <diesel macros>)
src/schema.rs:1:1: 1:40 note: in this expansion of infer_schema! (defined in src/lib.rs)
src/lib.rs:1:1: 1:1 help: run `rustc --explain E0412` to see a detailed explanation
src/lib.rs:1:1: 1:1 help: no candidates by the name of `Timestamptz` found in your project; maybe you misspelled the name or forgot to import an external crate?
src/lib.rs:1:1: 1:1 error: type name `Timestamptz` is undefined or not in scope [E0412]
src/lib.rs:1 #![feature(custom_derive, custom_attribute, plugin)]

...

<diesel macros>:38:1: 38:47 note: in this expansion of column! (defined in <diesel macros>)
<diesel macros>:5:1: 5:71 note: in this expansion of table_body! (defined in <diesel macros>)
src/schema.rs:1:1: 1:40 note: in this expansion of table! (defined in <diesel macros>)
src/schema.rs:1:1: 1:40 note: in this expansion of infer_schema! (defined in src/lib.rs)
src/lib.rs:1:1: 1:1 help: run `rustc --explain E0412` to see a detailed explanation
src/lib.rs:1:1: 1:1 help: no candidates by the name of `Timestamptz` found in your project; maybe you misspelled the name or forgot to import an external crate?
src/models.rs:16:18: 16:27 error: type name `Timestamp` is undefined or not in scope [E0412]
src/models.rs:16     pub created: Timestamp,
                              ^~~~~~~~~
src/models.rs:16:18: 16:27 help: run `rustc --explain E0412` to see a detailed explanation
src/models.rs:16:18: 16:27 help: you can import it into scope: `use diesel::types::Timestamp;`.
src/models.rs:17:18: 17:27 error: type name `Timestamp` is undefined or not in scope [E0412]
src/models.rs:17     pub updated: Timestamp
                              ^~~~~~~~~

看起来像是第一个错误，Timestamptz是infer_schema不知道如何解释表中已经存在的Postgresql类型的结果.至于第二个，我想如果显式导入Timestamp类型，我可以用它创建一个Post struct .

有没有什么明显的事情表明我做错了？

顺便说一句，我对Rust 和柴油机使用了相当多的代码生成，所以很容易丢失，但我认为这应该是一个简单的事情来完成.

Edit:

我用timestamp with time zone创建了这个表，它看起来像may not be supported yet:

CREATE TABLE post (
    ...
    created timestamp with time zone NOT NULL,
    updated timestamp with time zone
)

Edit 2:

我将models.rs改为如下所示，并消除了Timestamp未定义的错误.我还意识到，我需要在每个 struct 之上派生#[derive(Queryable)]个.下面的编译很好，但之前的Timestamptz错误仍然存在:

use diesel::types::Timestamp;

#[derive(Queryable)]
pub struct Author {
    pub id: i32,
    pub first_name: String,
    pub last_name: String,
    pub email: String
}

#[derive(Queryable)]
pub struct Post {
    pub id: i32,
    pub author: Author,
    pub title: String,
    pub body: String,
    pub published: bool,
    pub created: Timestamp,
    pub updated: Timestamp
}