Rust Diesel Library 使用 Timestamptz 反序列化 Postgres DateTIme，

Question

Error is:-

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

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

My up.sql is:--

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');

My model file: -

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>,
}

My test file:-

#[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);
    }
}

My Cargo file:-

[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 = "*"

My auto generated schema from diesel cli:-

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,
);

Problem only when I add datetimefield, If I remove it from sql and models, than it is not giving problem,

Answer 1

I think your problem is due to field order. The order of fields in your SQL does not match your model structs.

From Diesel Getting Started

Using #[derive(Queryable)] assumes that the order of fields on the Post struct matches the columns in the posts table, so make sure to define them in the order seen in the schema.rs file.

The error message said it couldn't convert a Bool to a timestamp, so that's why I think it mixed up your is_active with one of the date fields.