如何使用 Diesel 将 i64 与 Insertable 结合使用 [英] How to use i64 with Insertable using Diesel

问题描述

如何在 Diesel 中使用 i64/u64?

How do I use i64/u64 with Diesel?

我真的需要为原始类型实现 diesel::Expression trait 吗?

Do I really need to implement the diesel::Expression trait for the primitive type?

这是我的代码.

Cargo.toml:

[dependencies]
...
diesel = { version = "1.4.5", features = ["sqlite", "numeric"] }

migration/up.sql:

CREATE TABLE books (
  id INTEGER NOT NULL PRIMARY KEY,
  size INTEGER NOT NULL
);

schema.rs:

table! {
    books (id) {
        id -> Integer,
        size -> Integer,
    }
}

来源:

use crate::schema::books;

#[derive(Insertable, Queryable)]
#[table_name="books"]
pub struct BookRecord {
    pub id: Id,
    pub size: i64,
}

这会产生以下错误:

error[E0277]: the trait bound `i64: diesel::Expression` is not satisfied
 --> src/lib/models/book.rs:4:10
  |
4 | #[derive(Insertable, Queryable)]
  |          ^^^^^^^^^^ the trait `diesel::Expression` is not implemented for `i64`
  |
  = note: required because of the requirements on the impl of `diesel::expression::AsExpression<diesel::sql_types::Integer>` for `i64`
  = note: this error originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)

我该如何解决这个错误?

How do I resolve this error?

推荐答案

i64 对应于 BigInt 和 i32对应于Integer.将架构更改为使用 BigInt，或将数字更改为 i32.

i64 corresponds to BigInt and i32 corresponds to Integer. Either change your schema to use BigInt, or change your numbers to i32.

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