英文:

How to implement a trait on any type that implements PgExecutor?

问题

我有自己的特性来扩展`PgExecutor`特性提供的功能。

我想要在任何实现了`PgExecutor`的东西上实现这些特性，但老实说，我遇到了一些困难。

```rust
#[async_trait]
impl<'a, T> PgExecutorExt for T
    where T: PgExecutor<'a> + Sync
{
    async fn my_read_method(&self) -> anyhow::Result<()> {
        sqlx::query_as!(...)
        .fetch_one(self)
        .await?;

        Ok(())
    }
}

但我得到了以下错误：

未满足`&T: Executor<'_>`的特性约束
`Executor<'_>`特性未为`&T`实现

在.fetch_one(self)调用上。

有没有人知道发生了什么？谢谢！

<details>
<summary>英文:</summary>

I have my own trait to extend the functionality that the `PgExecutor` trait provides.

I want to implement these trait on anything that implements `PgExecutor` but I&#39;m honestly having a hard time.


```rust
#[async_trait]
impl&lt;&#39;a, T&gt; PgExecutorExt for T
    where T: PgExecutor&lt;&#39;a&gt; + Sync
 {
    async fn my_read_method(&amp;self) -&gt; anyhow::Result&lt;()&gt; {
        sqlx::query_as!(...)
        .fetch_one(self)
        .await?;

        Ok(())
    }
}

But I'm getting the following error:

the trait bound `&T: Executor<'_>` is not satisfied
the trait `Executor<'_>` is not implemented for `&T` 

On the .fetch_one(self) call

anyone has any clue on what is going on??
Thank you!

答案1

得分: 1

Executor::fetch_one() 函数接受 self，而不是 &self。您需要在您的特性定义和此实现中将 &self 更改为 self，这应该会解决问题。

英文:

The Executor::fetch_one() function takes self, not &self. You need to change &self to self in your trait definition and this implementation, and that should fix the issue.