Question

如何将i64 / u64与柴油一起使用？

我真的需要为原始类型实现diesel::Expression特性吗？

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,
}

这会出现以下错误：

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)

如何解决此错误？

Answer 1

i64 corresponds to BigInt和i32 corresponds to Integer。更改架构以使用BigInt，或将数字更改为i32。

如何通过柴油使用i64和Insertable

1 个答案: