Rust Diesel 库使用 Timestamptz 反序列化 Postgres DateTIme，

Question

错误是：-

  > src/lib.rs:45:14
       |
    45 |             .load::<Store>(&conn)
       |              ^^^^ the trait 

`diesel::deserialize::FromSql<diesel::sql_types::Timestamptz, _>` is not implemented for `bool`

我的 up.sql 是：--

CREATE TABLE store (
    id SERIAL PRIMARY KEY,
    name VARCHAR(500) NOT NULL,
    description VARCHAR(2000) NOT NULL,
    created_at timestamp with TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP,
    updated_at timestamp with TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP,
    is_active boolean DEFAULT 'f' NOT NULL,
    created_by integer NOT NULL,
    address_id integer NOT NULL
);

SELECT diesel_manage_updated_at('store');

我的模型文件：-

use diesel::{Insertable, Queryable};
use serde::{Deserialize, Serialize};
use chrono::{ DateTime, Utc };

use crate::schema::{store, item, store_item};

use std::convert::From;

#[derive(Deserialize, Serialize, Queryable)]
pub struct Store {
    pub id: i32,
    pub name: String,
    pub description: String,
    pub is_active: bool,
    pub created_by: i32,
    pub address_id: i32,
    pub created_at: DateTime<Utc>,
    pub updated_at: DateTime<Utc>,
}

我的测试文件：-

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

pub mod schema;
pub mod models;



#[cfg(test)]
mod tests {
    #[test]
    fn it_works() {

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

        dotenv().ok();

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

        let sid: i32 = 1;
        use crate::models::{Store, NewStore};
        use crate::schema::store::dsl::*;

        let new_store = NewStore {
            name: "Top in town stores".to_owned(),
            description: "this is top in town stores".to_owned(),
            is_active: true,
            created_by: 22,
            address_id: 3322
        };

        let sam: usize = diesel::insert_into(store).values(&new_store).execute(&conn).unwrap();

        let user = store
            .filter(id.eq(sid))
            .limit(1)
            .load::<Store>(&conn)
            .expect("Error loading posts");

        assert_eq!(1, 1);
    }
}

我的货物文件：-

[package]
name = "database"
version = "0.1.0"
authors = ["spiderman"]
edition = "2018"


# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
diesel = { version="1.4.5", features = ["postgres", "extras", "chrono"] }

chrono = { version = "0.4", features = ["serde", "rustc-serialize"] }

serde = { version = "1.0", features = ["derive"] }
serde_json = "1.0"
dotenv = "*"

我从柴油 cli 自动生成的架构：-

table! {
    item (id) {
        id -> Int4,
        name -> Varchar,
        description -> Varchar,
        created_at -> Timestamptz,
        updated_at -> Timestamptz,
        is_active -> Bool,
        created_by -> Int4,
    }
}

table! {
    store (id) {
        id -> Int4,
        name -> Varchar,
        description -> Varchar,
        created_at -> Timestamptz,
        updated_at -> Timestamptz,
        is_active -> Bool,
        created_by -> Int4,
        address_id -> Int4,
    }
}

table! {
    store_item (id) {
        id -> Int4,
        store_id -> Nullable<Int4>,
        item_id -> Nullable<Int4>,
        created_at -> Timestamptz,
        updated_at -> Timestamptz,
        is_active -> Bool,
        created_by -> Int4,
    }
}

joinable!(store_item -> item (item_id));
joinable!(store_item -> store (store_id));

allow_tables_to_appear_in_same_query!(
    item,
    store,
    store_item,
);

仅当我添加 datetimefield 时出现问题，如果我将其从 sql 和模型中删除，则不会出现问题，

Answer 1

我认为您的问题是由于字段顺序造成的。 SQL 中的字段顺序与模型结构不匹配。

来自Diesel Getting Started

使用 #[derive(Queryable)] 假设 Post 结构中的字段顺序与 posts 表中的列相匹配，因此请确保按照 schema.rs 文件中的顺序定义它们。

错误消息说它无法将 Bool 转换为时间戳，所以我认为它会将您的 is_active 与日期字段之一混淆。