Rust 无法将 Postgres 数值类型表示为 BigDecimal 类型。

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英文:

Rust cannot represent Postgres numeric type as BigDecimal type

问题

I am writing simple rust web application using actix-web and sqlx.
我正在编写一个简单的Rust Web应用程序,使用actix-websqlx

I have struct Book with price field which should be mapped to postgres NUMERIC type.
我有一个名为Book的结构体,其中包含应该映射到PostgreSQL的NUMERIC类型的price字段。

First I got error from sqlx that it was expecting bigdecimal type and suggested to enable this feature from cargo configuration, so I did.
首先,我收到了来自sqlx的错误,它期望bigdecimal类型,并建议从Cargo配置中启用此功能,所以我这样做了。

Then I imported BigDecimal from sqlx types and tried to use this type in my struct.
然后,我从sqlx类型中导入了BigDecimal并尝试在我的结构体中使用这个类型。

But I get this error:
但我收到了以下错误:

12 |     pub price: BigDecimal,
   |     ^^^ the trait `configuration::_::_serde::Deserialize<'_>` is not implemented for `BigDecimal`

I tried to find solution to this problem, one possible solution was to use bigdecimal crate directly with serde enabled. So I tried to use bigdecimal type instead of sqlx one:
我尝试找到解决这个问题的方法,一个可能的解决方案是直接使用启用了serdebigdecimal crate。所以我尝试使用bigdecimal类型代替sqlx

use bigdecimal::BigDecimal;

But now I got different error:
但现在我收到了不同的错误:

the trait `sqlx::Type<Postgres>` is not implemented for `bigdecimal::BigDecimal`

Here is code I am using:
这是我正在使用的代码:

Book struct:
Book结构体:

use chrono::{DateTime, Utc,};
use chrono::serde::ts_seconds;
//use sqlx::types::BigDecimal;
use bigdecimal::BigDecimal;

#[derive(serde::Deserialize)]
pub struct Book {
    pub author: String,
    pub title: String,
    pub pages: i32,
    pub price: BigDecimal,
    #[serde(with = "ts_seconds")]
    pub published_at: DateTime<Utc>
}

function that tries to insert Book data into database:
尝试将Book数据插入数据库的函数:

pub async fn insert_book(data: &Book, pool: &PgPool) -> Result<(), sqlx::Error> {
    sqlx::query!(
        r#"
            INSERT INTO books
            (id, author, title, pages, price, published_at)
            VALUES ($1, $2, $3, $4, $5, $6)
        "#,
        Uuid::new_v4(),
        data.author,
        data.title,
        data.pages,
        data.price,
        data.published_at
    )
    .execute(pool)
    .await
    .map_err(|e| e)?;

    Ok(())
}

Simple POST endpoint:
简单的POST端点:

#[post("/book")]
pub async fn add_new_book(data: web::Form<Book>, pool: web::Data<PgPool>) -> impl Responder {
    match insert_book(&data, &pool).await {
        Ok(_) => HttpResponse::Ok(),
        Err(e) => HttpResponse::InternalServerError()
    }
}

Cargo.toml
Cargo.toml文件:

[dependencies]
secrecy = { version = "0.8", features = ["serde"] }
actix-web = "4.3.1"
serde = { version = "1", features = ["derive"]}
tokio = { version = "1", features = ["macros", "rt-multi-thread"] }
uuid = { version = "1.3.4", features = ["v4"] }
config = "0.11"
chrono = { version = "0.4.26", features = ["serde"] }
bigdecimal = { version = "0.2.0", features = ["serde"] }

[dependencies.sqlx]
version = "0.6.3"
default-features = false
features = [
    "runtime-actix-rustls",
    "macros",
    "postgres",
    "uuid",
    "chrono",
    "migrate",
    "bigdecimal"
]

Not sure how to fix this problem, any help will be appreciated.
不确定如何解决这个问题,将不胜感激任何帮助。

英文:

I am writing simple rust web application using actix-web and sqlx.
I have struct Book with price field which should be mapped to postgres NUMERIC type. First I got error from sqlx that it was expecting bigdecimal type and suggested to enable this feature from cargo configuration, so I did. Then I imported BigDecimal from sqlx types and tried to use this type in my struct.

use sqlx::types::BigDecimal;

But I get this error:

12 |     pub price: BigDecimal,
   |     ^^^ the trait `configuration::_::_serde::Deserialize&lt;&#39;_&gt;` is not implemented for `BigDecimal`

I tried to find solution to this problem, one possible solution was to use bigdecimal crate directly with serde enabled. So I tried to use bigdecimal type instead of sqlx one:

use bigdecimal::BigDecimal;

But now I got different error:

the trait `sqlx::Type&lt;Postgres&gt;` is not implemented for `bigdecimal::BigDecimal`

Here is code I am using:

Book struct:

use chrono::{DateTime, Utc,};
use chrono::serde::ts_seconds;
//use sqlx::types::BigDecimal;
use bigdecimal::BigDecimal;


#[derive(serde::Deserialize)]
pub struct Book {
    pub author: String,
    pub title: String,
    pub pages: i32,
    pub price: BigDecimal,
    #[serde(with = &quot;ts_seconds&quot;)]
    pub published_at: DateTime&lt;Utc&gt;
}

function that tries to insert Book data into database:

pub async fn insert_book(data: &amp;Book, pool: &amp;PgPool) -&gt; Result&lt;(), sqlx::Error&gt; {
    sqlx::query!(
        r#&quot;
            INSERT INTO books
            (id, author, title, pages, price, published_at)
            VALUES ($1, $2, $3, $4, $5, $6)
        &quot;#,
        Uuid::new_v4(),
        data.author,
        data.title,
        data.pages,
        data.price,
        data.published_at
    )
        .execute(pool)
        .await
        .map_err(|e| {
            e
        })?;

    Ok(())
}

Simple POST endpoint:

#[post(&quot;/book&quot;)]
pub async fn add_new_book(data: web::Form&lt;Book&gt;, pool: web::Data&lt;PgPool&gt;) -&gt; impl Responder {
    match insert_book(&amp;data, &amp;pool).await {
        Ok(_) =&gt; HttpResponse::Ok(),
        Err(e) =&gt; HttpResponse::InternalServerError()
    }
}

Cargo.toml

[dependencies]
secrecy = { version = &quot;0.8&quot;, features = [&quot;serde&quot;] }
actix-web = &quot;4.3.1&quot;
serde = { version = &quot;1&quot;, features = [&quot;derive&quot;]}
tokio = { version = &quot;1&quot;, features = [&quot;macros&quot;, &quot;rt-multi-thread&quot;] }
uuid = { version = &quot;1.3.4&quot;, features = [&quot;v4&quot;] }
config = &quot;0.11&quot;
chrono = { version = &quot;0.4.26&quot;, features = [&quot;serde&quot;] }
bigdecimal = { version = &quot;0.2.0&quot;, features = [&quot;serde&quot;] }


[dependencies.sqlx]
version = &quot;0.6.3&quot;
default-features = false
features = [
    &quot;runtime-actix-rustls&quot;,
    &quot;macros&quot;,
    &quot;postgres&quot;,
    &quot;uuid&quot;,
    &quot;chrono&quot;,
    &quot;migrate&quot;,
    &quot;bigdecimal&quot;
]

Not sure how to fix this problem, any help will be appreciated.

答案1

得分: 4

你需要匹配 sqlx 使用的 bigdecimal 版本(对于 sqlx 0.6.3,应使用 bigdecimal 0.3.0)。

这实际上是 sqlx_core 的依赖项

英文:

You need to match the version of bigdecimal that sqlx uses (for sqlx 0.6.3, that would be bigdecimal 0.3.0).

It's actually a dependency of sqlx_core

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  • 本文由 发表于 2023年6月15日 05:04:57
  • 转载请务必保留本文链接:https://go.coder-hub.com/76477527.html
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