How to determine whether the select result is no record found?

[kggg]

怎么判断select结果是no record found？

pub async fn select_todo_by_id(id: u64) -> Result<Todolist, rbatis::rbdc::Error> { let rs = RB .query_decode("select * from todolist where id = ?", vec![Value::U64(id)]) .await?; Ok(rs) }
现在错误打印出来的是以下信息
E("error while decoding value: invalid type: unit value, expected struct Todolist")

[zhuxiujia]

Todolist

Todolist 这个结构体 解析uint失败的column成员

[kggg]

todolist中没有存在的记录就会报这个错， 有记录就没有问题，查询结果正常。

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---

If there is no record in the todolist, this error will be reported. If there is a record, there will be no problem and the query result will be normal.

[zhuxiujia]

todolist中没有存在的记录就会报这个错， 有记录就没有问题，查询结果正常。

可以告诉我数据库类型，表结构体的定义，以及 数据库表的数据吗？

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---

If there is no record in the todolist, this error will be reported. If there is a record, there will be no problem and the query result will be normal.

Can you tell me the database type, the definition of the table structure, and the data of the database table?

[kggg]

mysql 8

mysql> desc todolist;
+------------+-----------------+------+-----+---------+----------------+
| Field      | Type            | Null | Key | Default | Extra          |
+------------+-----------------+------+-----+---------+----------------+
| id         | bigint unsigned | NO   | PRI | NULL    | auto_increment |
| created_at | datetime(3)     | NO   |     | NULL    |                |
| updated_at | datetime(3)     | NO   |     | NULL    |                |
| deleted_at | datetime(3)     | YES  | MUL | NULL    |                |
| type_id    | bigint          | YES  |     | NULL    |                |
| user       | varchar(20)     | NO   |     | NULL    |                |
| title      | varchar(30)     | NO   |     | NULL    |                |
| status     | int             | NO   |     | 0       |                |
| level      | varchar(8)      | NO   |     | 一般    |                |
| content    | text            | NO   |     | NULL    |                |
+------------+-----------------+------+-----+---------+----------------+
10 rows in set (0.00 sec)

···
#[derive(Debug, Deserialize, PartialEq, Eq, Clone, Serialize)]
pub struct Todolist {
id: Option,
created_at: DateTime,
updated_at: DateTime,
deleted_at: Option,
type_id: u64,
user: String,
title: String,
status: u8,
level: String,
content: String,
}

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---

mysql 8

mysql> desc todolist;
+------------+-----------------+------+-----+---------+----------------+
| Field      | Type            | Null | Key | Default | Extra          |
+------------+-----------------+------+-----+---------+----------------+
| id         | bigint unsigned | NO   | PRI | NULL    | auto_increment |
| created_at | datetime(3)     | NO   |     | NULL    |                |
| updated_at | datetime(3)     | NO   |     | NULL    |                |
| deleted_at | datetime(3)     | YES  | MUL | NULL    |                |
| type_id    | bigint          | YES  |     | NULL    |                |
| user       | varchar(20)     | NO   |     | NULL    |                |
| title      | varchar(30)     | NO   |     | NULL    |                |
| status     | int             | NO   |     | 0       |                |
| level      | varchar(8)      | NO   |     | 一般    |                |
| content    | text            | NO   |     | NULL    |                |
+------------+-----------------+------+-----+---------+----------------+
10 rows in set (0.00 sec)

···
#[derive(Debug, Deserialize, PartialEq, Eq, Clone, Serialize)]
pub struct Todolist {
id: Option,
created_at: DateTime,
updated_at: DateTime,
deleted_at: Option,
type_id: u64,
user: String,
title: String,
status: u8,
level: String,
content: String,
}

[zhuxiujia]

mysql 8

mysql> desc todolist;
+------------+-----------------+------+-----+---------+----------------+
| Field      | Type            | Null | Key | Default | Extra          |
+------------+-----------------+------+-----+---------+----------------+
| id         | bigint unsigned | NO   | PRI | NULL    | auto_increment |
| created_at | datetime(3)     | NO   |     | NULL    |                |
| updated_at | datetime(3)     | NO   |     | NULL    |                |
| deleted_at | datetime(3)     | YES  | MUL | NULL    |                |
| type_id    | bigint          | YES  |     | NULL    |                |
| user       | varchar(20)     | NO   |     | NULL    |                |
| title      | varchar(30)     | NO   |     | NULL    |                |
| status     | int             | NO   |     | 0       |                |
| level      | varchar(8)      | NO   |     | 一般    |                |
| content    | text            | NO   |     | NULL    |                |
+------------+-----------------+------+-----+---------+----------------+
10 rows in set (0.00 sec)

··· #[derive(Debug, Deserialize, PartialEq, Eq, Clone, Serialize)] pub struct Todolist { id: Option, created_at: DateTime, updated_at: DateTime, deleted_at: Option, type_id: u64, user: String, title: String, status: u8, level: String, content: String, }

todolist中没有存在的记录就会报这个错，
1 Result<Todolist, rbatis::rbdc::Error> 应该改成 Result<Option<Todolist>, rbatis::rbdc::Error>
这样查不到记录的时候是None才对
2 deleted_at 和type_id 在表里可以为null，那么这2个column 都应该用Option<xxx>才对

[kggg]

谢谢, OK 了

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---

Thank you, OK

[zhuxiujia]

谢谢, OK 了

我更新rbs序列化框架，提示更新为error while decoding value: invalid type: Option value, expected struct Activity 这样可读性更高。你可以使用cargo update命令更新依赖即可

[zhuxiujia]

怎么判断select结果是no record found？

pub async fn select_todo_by_id(id: u64) -> Result<Todolist, rbatis::rbdc::Error> { let rs = RB .query_decode("select * from todolist where id = ?", vec![Value::U64(id)]) .await?; Ok(rs) } 现在错误打印出来的是以下信息 E("error while decoding value: invalid type: unit value, expected struct Todolist")

推荐使用crud! 宏内置的函数，更方便。

#[macro_use]
extern crate rbatis;

pub mod init;

use crate::init::init_db;
use rbatis::rbdc::datetime::DateTime;
use serde_json::json;

/// table
#[derive(Clone, Debug, serde::Serialize, serde::Deserialize)]
pub struct Activity {
    pub id: Option<String>,
    pub name: Option<String>,
    pub pc_link: Option<String>,
    pub h5_link: Option<String>,
    pub pc_banner_img: Option<String>,
    pub h5_banner_img: Option<String>,
    pub sort: Option<String>,
    pub status: Option<i32>,
    pub remark: Option<String>,
    pub create_time: Option<DateTime>,
    pub version: Option<i64>,
    pub delete_flag: Option<i32>,
}
crud!(Activity {});
impl_select!(Activity{select_all_by_id(id:&str,name:&str) => "`where id = #{id} and name = #{name}`"});
impl_select!(Activity{select_by_id(id:&str) -> Option => "`where id = #{id} limit 1`"});

#[tokio::main]
pub async fn main() {
    fast_log::init(
        fast_log::Config::new()
            .console()
            .level(log::LevelFilter::Debug),
    )
    .expect("rbatis init fail");
    let rb = init_db().await;

    let data = Activity::select_by_column(&rb, "id", "1").await;
    println!("select_by_id = {}", json!(data));

    let data = Activity::select_all_by_id(&rb, "1", "1").await;
    println!("select_all_by_id = {}", json!(data));

    let data = Activity::select_by_id(&rb, "1").await;
    println!("select_by_id = {}", json!(data));
}