[英]Rust/Diesel: How to query and insert into postgres tables which have uuid
我有以下由 Diesel 生成的架构:
table! {
user (id) {
id -> Uuid,
name -> Text
}
和相关的模型
use diesel::{
self,
Queryable,
Insertable,
};
use diesel::prelude::*;
use diesel::sql_types::Uuid;
use super::schema::user;
#[derive(Queryable)]
pub struct User {
pub id: Uuid,
pub name: String,
}
impl User {
pub fn get(id: i32, connection: &PgConnection) -> Vec<User> {
user::table.load::<User>(connection).unwrap()
}
}
当我尝试编译它时出现错误,它说:
21 | user::table.load::<User>(connection).unwrap()
| ^^^^ the trait `diesel::Queryable<diesel::sql_types::Uuid, diesel::pg::Pg>` is not implemented for `diesel::sql_types::Uuid`
如果我尝试插入,我会收到类似的错误,指出未实现Expression
。
这可能是我的依赖项的问题还是我可能忘记添加到模型中的问题?
[dependencies]
rocket = "0.4.0-rc.1"
serde = "1.0"
serde_derive = "1.0"
serde_json = "1.0"
diesel = { version = "1.0.0", features = ["postgres", "uuid"] }
r2d2 = "*"
r2d2-diesel = "*"
[dependencies.rocket_contrib]
version = "0.4.0-rc.1"
default-features = false
features = ["json", "diesel_postgres_pool", "uuid"]
struct 中的类型需要是 Rust 类型而不是 SQL 类型,特别是来自uuid crate 的Uuid
(在 Diesel 1.3 中,Diesel 仅支持 0.6 版)。 在问题的代码中, Uuid
被扩展为一个diesel::sql_types::Uuid
#[derive(Queryable)]
pub struct User {
pub id: uuid::Uuid,
pub name: String,
}
刚刚也花了很多时间解决这个问题。 从 Diesel 1.4.5 开始,您可以添加最新版本的uuid
,但您必须在 Diesel 上指定uuidv07
功能。
您的Cargo.toml
应如下所示:
uuid = { version = "0.8.2", features = ["serde", "v4"] }
diesel = { version = "1.4.5", features = ["chrono", "postgres", "r2d2", "uuidv07"] }
来源: https : //github.com/diesel-rs/diesel/issues/2348
注意:另外,就像@canab 所说的,结构上的Uuid
类型应该来自uuid
库,而不是 Diesel SQL 类型。
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