schema table 存在 rust diesel 方法 `filter`，但不满足其特征界限？
rust diesel method `filter` exists for schema table, but its trait bounds were not satisfied?
这是我的工作环境：
- rustc - 1.57.0
- 货物 - 1.57.0
- 柴油机 - 1.4.8 具有 mysql 功能
项目结构如下：
- src
- lib.rs
+ quant
- mod.rs
+ common
- mod.rs
+ persistence
- mod.rs
- database.rs
- model.rs
- schema.rs
Cargo.toml
diesel.toml
这是lib.rs：
#[macro_use]
extern crate diesel;
pub mod quant;
这是model.rs：
use diesel::Queryable;
#[derive(Queryable)]
pub struct NetWorthModel {
pub fund_code: String,
pub date: String,
pub create_time: i64,
pub update_time: i64,
pub payload: String,
}
这是schema.rs：
use diesel::table;
table! {
tb_net_worth(fund_code) {
fund_code -> VarChar,
date -> Date,
create_time -> BigInt,
update_time -> BigInt,
payload -> Text,
}
}
这是database.rs：
use crate::quant::common::persistence::model::NetWorthModel;
use diesel::mysql::MysqlConnection;
use diesel::sql_types;
use diesel::Connection;
use chrono;
type YaDate = chrono::prelude::Date<chrono::prelude::Local>;
pub struct Database {
connection: MysqlConnection,
}
impl Database {
const ASC: &'static str = "ASC";
const DESC: &'static str = "DESC";
pub fn get() -> Database {
Database::new()
}
pub fn shutdown() {}
fn new() -> Database {
use crate::quant::config;
let engine = "mysql";
let username = "root";
let password = "123456";
let host = "localhost";
let port = 3306;
let db = "test";
let url = format!(
"{}://{}:{}@{}:{}/{}",
engine, username, password, host, port, db
);
let connection = MysqlConnection::establish(&url)
.expect(&format!("Failed to connect database:{}-{}", engine, db));
Database { connection }
}
pub fn paged_query_net_worth(
&mut self,
fund_code: &str,
order_by: &str,
start_date: YaDate,
end_date: YaDate,
page_index: i32,
page_size: i32,
) -> Vec<NetWorthModel> {
use super::schema::tb_net_worth::dsl;
let query = dsl::tb_net_worth
.filter(dsl::fund_code.eq(fund_code))
.filter(dsl::date.ge(start_date))
.filter(dsl::date.lt(end_date));
let query = if order_by == Database::ASC {
query.order(dsl::date)
} else {
query.order(dsl::date.desc())
};
query
.limit(page_size)
.offset(page_index * page_size)
.load::<NetWorthModel>(&self.connection)
.unwrap()
}
}
编译错误如下：
error[E0599]: the method `filter` exists for struct `table`, but its trait bounds were not satisfied
--> src/quant/common/persistence/database.rs:74:14
|
74 | .filter(dsl::fund_code.eq(fund_code))
| ^^^^^^ method cannot be called on `table` due to unsatisfied trait bounds
|
::: src/quant/common/persistence/schema.rs:5:1
|
5 | / table! {
6 | | tb_net_worth(fund_code) {
7 | | fund_code -> VarChar,
8 | | date -> Date,
... |
12 | | }
13 | | }
| | -
| | |
| |_method `filter` not found for this
| doesn't satisfy `table: Iterator`
|
= note: the following trait bounds were not satisfied:
`table: Iterator`
which is required by `&mut table: Iterator`
note: the following trait must be implemented
--> /Users/rolin/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/traits/iterator.rs:55:1
|
55 | / pub trait Iterator {
56 | | /// The type of the elements being iterated over.
57 | | #[stable(feature = "rust1", since = "1.0.0")]
58 | | type Item;
... |
3457 | | }
3458 | | }
| |_^
= help: items from traits can only be used if the trait is in scope
help: the following traits are implemented but not in scope; perhaps add a `use` for one of them:
|
3 | use std::iter::Iterator;
|
3 | use crate::diesel::query_dsl::filter_dsl::FilterDsl;
|
3 | use crate::diesel::QueryDsl;
|
3 | use log4rs::filter::Filter;
|
error[E0599]: the method `eq` exists for struct `columns::fund_code`, but its trait bounds were not satisfied
--> src/quant/common/persistence/database.rs:74:36
|
74 | .filter(dsl::fund_code.eq(fund_code))
| ^^ method cannot be called on `columns::fund_code` due to unsatisfied trait bounds
|
::: src/quant/common/persistence/schema.rs:5:1
|
5 | / table! {
6 | | tb_net_worth(fund_code) {
7 | | fund_code -> VarChar,
8 | | date -> Date,
... |
12 | | }
13 | | }
| | -
| | |
| |_method `eq` not found for this
| doesn't satisfy `columns::fund_code: Iterator`
|
= note: the following trait bounds were not satisfied:
`columns::fund_code: Iterator`
which is required by `&mut columns::fund_code: Iterator`
note: the following trait must be implemented
--> /Users/rolin/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/traits/iterator.rs:55:1
|
55 | / pub trait Iterator {
56 | | /// The type of the elements being iterated over.
57 | | #[stable(feature = "rust1", since = "1.0.0")]
58 | | type Item;
... |
3457 | | }
3458 | | }
| |_^
= help: items from traits can only be used if the trait is in scope
help: the following trait is implemented but not in scope; perhaps add a `use` for it:
|
3 | use crate::diesel::ExpressionMethods;
|
error[E0599]: the method `ge` exists for struct `columns::date`, but its trait bounds were not satisfied
--> src/quant/common/persistence/database.rs:75:31
|
75 | .filter(dsl::date.ge(start_date))
| ^^ method cannot be called on `columns::date` due to unsatisfied trait bounds
|
::: src/quant/common/persistence/schema.rs:5:1
|
5 | / table! {
6 | | tb_net_worth(fund_code) {
7 | | fund_code -> VarChar,
8 | | date -> Date,
... |
12 | | }
13 | | }
| | -
| | |
| |_method `ge` not found for this
| doesn't satisfy `columns::date: Iterator`
|
= note: the following trait bounds were not satisfied:
`columns::date: Iterator`
which is required by `&mut columns::date: Iterator`
note: the following trait must be implemented
--> /Users/rolin/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/traits/iterator.rs:55:1
|
55 | / pub trait Iterator {
56 | | /// The type of the elements being iterated over.
57 | | #[stable(feature = "rust1", since = "1.0.0")]
58 | | type Item;
... |
3457 | | }
3458 | | }
| |_^
= help: items from traits can only be used if the trait is in scope
help: the following trait is implemented but not in scope; perhaps add a `use` for it:
|
3 | use crate::diesel::ExpressionMethods;
|
error[E0599]: the method `lt` exists for struct `columns::date`, but its trait bounds were not satisfied
--> src/quant/common/persistence/database.rs:76:31
|
76 | .filter(dsl::date.lt(end_date));
| ^^ method cannot be called on `columns::date` due to unsatisfied trait bounds
|
::: src/quant/common/persistence/schema.rs:5:1
|
5 | / table! {
6 | | tb_net_worth(fund_code) {
7 | | fund_code -> VarChar,
8 | | date -> Date,
... |
12 | | }
13 | | }
| | -
| | |
| |_method `lt` not found for this
| doesn't satisfy `columns::date: Iterator`
|
= note: the following trait bounds were not satisfied:
`columns::date: Iterator`
which is required by `&mut columns::date: Iterator`
note: the following trait must be implemented
--> /Users/rolin/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/traits/iterator.rs:55:1
|
55 | / pub trait Iterator {
56 | | /// The type of the elements being iterated over.
57 | | #[stable(feature = "rust1", since = "1.0.0")]
58 | | type Item;
... |
3457 | | }
3458 | | }
| |_^
= help: items from traits can only be used if the trait is in scope
help: the following trait is implemented but not in scope; perhaps add a `use` for it:
|
3 | use crate::diesel::ExpressionMethods;
|
error[E0599]: no method named `desc` found for struct `columns::date` in the current scope
--> src/quant/common/persistence/database.rs:80:35
|
80 | query.order(dsl::date.desc())
| ^^^^ method not found in `columns::date`
|
::: /Users/rolin/.cargo/registry/src/github.com-1ecc6299db9ec823/diesel-1.4.8/src/expression_methods/global_expression_methods.rs:397:8
|
397 | fn desc(self) -> Desc<Self> {
| ---- the method is available for `columns::date` here
|
::: src/quant/common/persistence/schema.rs:5:1
|
5 | / table! {
6 | | tb_net_worth(fund_code) {
7 | | fund_code -> VarChar,
8 | | date -> Date,
... |
12 | | }
13 | | }
| |_- method `desc` not found for this
|
= help: items from traits can only be used if the trait is in scope
help: the following trait is implemented but not in scope; perhaps add a `use` for it:
|
3 | use crate::diesel::ExpressionMethods;
|
For more information about this error, try `rustc --explain E0599`.
你能帮我解决一下吗？
错误消息包含帮助注释，可以将您推向正确的方向：
the following traits are implemented but not in scope
diesel提供的函数filter、eq、ge、lt、desc都是通过traits实现的。并且必须将特征纳入范围以供使用。您需要几个最常见的柴油特性：QueryDsl and ExpressionMethods.
所以将这些添加到您的导入中：
use diesel::expression_methods::ExpressionMethods;
use diesel::query_dsl::QueryDsl;
或者，如果您的文件非常重柴油，请考虑使用通配符导入许多柴油最常见类型的前奏：
use diesel::prelude::*;
提到 Iterator 的错误是转移注意力的错误。默认情况下，Iterator 特征总是在范围内，它具有名称匹配的函数，并且它在 &mut T 上有一个全面的实现，因为 T 是一个 Iterator.
这是我的工作环境：
- rustc - 1.57.0
- 货物 - 1.57.0
- 柴油机 - 1.4.8 具有 mysql 功能
项目结构如下：
- src
- lib.rs
+ quant
- mod.rs
+ common
- mod.rs
+ persistence
- mod.rs
- database.rs
- model.rs
- schema.rs
Cargo.toml
diesel.toml
这是lib.rs：
#[macro_use]
extern crate diesel;
pub mod quant;
这是model.rs：
use diesel::Queryable;
#[derive(Queryable)]
pub struct NetWorthModel {
pub fund_code: String,
pub date: String,
pub create_time: i64,
pub update_time: i64,
pub payload: String,
}
这是schema.rs：
use diesel::table;
table! {
tb_net_worth(fund_code) {
fund_code -> VarChar,
date -> Date,
create_time -> BigInt,
update_time -> BigInt,
payload -> Text,
}
}
这是database.rs：
use crate::quant::common::persistence::model::NetWorthModel;
use diesel::mysql::MysqlConnection;
use diesel::sql_types;
use diesel::Connection;
use chrono;
type YaDate = chrono::prelude::Date<chrono::prelude::Local>;
pub struct Database {
connection: MysqlConnection,
}
impl Database {
const ASC: &'static str = "ASC";
const DESC: &'static str = "DESC";
pub fn get() -> Database {
Database::new()
}
pub fn shutdown() {}
fn new() -> Database {
use crate::quant::config;
let engine = "mysql";
let username = "root";
let password = "123456";
let host = "localhost";
let port = 3306;
let db = "test";
let url = format!(
"{}://{}:{}@{}:{}/{}",
engine, username, password, host, port, db
);
let connection = MysqlConnection::establish(&url)
.expect(&format!("Failed to connect database:{}-{}", engine, db));
Database { connection }
}
pub fn paged_query_net_worth(
&mut self,
fund_code: &str,
order_by: &str,
start_date: YaDate,
end_date: YaDate,
page_index: i32,
page_size: i32,
) -> Vec<NetWorthModel> {
use super::schema::tb_net_worth::dsl;
let query = dsl::tb_net_worth
.filter(dsl::fund_code.eq(fund_code))
.filter(dsl::date.ge(start_date))
.filter(dsl::date.lt(end_date));
let query = if order_by == Database::ASC {
query.order(dsl::date)
} else {
query.order(dsl::date.desc())
};
query
.limit(page_size)
.offset(page_index * page_size)
.load::<NetWorthModel>(&self.connection)
.unwrap()
}
}
编译错误如下：
error[E0599]: the method `filter` exists for struct `table`, but its trait bounds were not satisfied
--> src/quant/common/persistence/database.rs:74:14
|
74 | .filter(dsl::fund_code.eq(fund_code))
| ^^^^^^ method cannot be called on `table` due to unsatisfied trait bounds
|
::: src/quant/common/persistence/schema.rs:5:1
|
5 | / table! {
6 | | tb_net_worth(fund_code) {
7 | | fund_code -> VarChar,
8 | | date -> Date,
... |
12 | | }
13 | | }
| | -
| | |
| |_method `filter` not found for this
| doesn't satisfy `table: Iterator`
|
= note: the following trait bounds were not satisfied:
`table: Iterator`
which is required by `&mut table: Iterator`
note: the following trait must be implemented
--> /Users/rolin/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/traits/iterator.rs:55:1
|
55 | / pub trait Iterator {
56 | | /// The type of the elements being iterated over.
57 | | #[stable(feature = "rust1", since = "1.0.0")]
58 | | type Item;
... |
3457 | | }
3458 | | }
| |_^
= help: items from traits can only be used if the trait is in scope
help: the following traits are implemented but not in scope; perhaps add a `use` for one of them:
|
3 | use std::iter::Iterator;
|
3 | use crate::diesel::query_dsl::filter_dsl::FilterDsl;
|
3 | use crate::diesel::QueryDsl;
|
3 | use log4rs::filter::Filter;
|
error[E0599]: the method `eq` exists for struct `columns::fund_code`, but its trait bounds were not satisfied
--> src/quant/common/persistence/database.rs:74:36
|
74 | .filter(dsl::fund_code.eq(fund_code))
| ^^ method cannot be called on `columns::fund_code` due to unsatisfied trait bounds
|
::: src/quant/common/persistence/schema.rs:5:1
|
5 | / table! {
6 | | tb_net_worth(fund_code) {
7 | | fund_code -> VarChar,
8 | | date -> Date,
... |
12 | | }
13 | | }
| | -
| | |
| |_method `eq` not found for this
| doesn't satisfy `columns::fund_code: Iterator`
|
= note: the following trait bounds were not satisfied:
`columns::fund_code: Iterator`
which is required by `&mut columns::fund_code: Iterator`
note: the following trait must be implemented
--> /Users/rolin/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/traits/iterator.rs:55:1
|
55 | / pub trait Iterator {
56 | | /// The type of the elements being iterated over.
57 | | #[stable(feature = "rust1", since = "1.0.0")]
58 | | type Item;
... |
3457 | | }
3458 | | }
| |_^
= help: items from traits can only be used if the trait is in scope
help: the following trait is implemented but not in scope; perhaps add a `use` for it:
|
3 | use crate::diesel::ExpressionMethods;
|
error[E0599]: the method `ge` exists for struct `columns::date`, but its trait bounds were not satisfied
--> src/quant/common/persistence/database.rs:75:31
|
75 | .filter(dsl::date.ge(start_date))
| ^^ method cannot be called on `columns::date` due to unsatisfied trait bounds
|
::: src/quant/common/persistence/schema.rs:5:1
|
5 | / table! {
6 | | tb_net_worth(fund_code) {
7 | | fund_code -> VarChar,
8 | | date -> Date,
... |
12 | | }
13 | | }
| | -
| | |
| |_method `ge` not found for this
| doesn't satisfy `columns::date: Iterator`
|
= note: the following trait bounds were not satisfied:
`columns::date: Iterator`
which is required by `&mut columns::date: Iterator`
note: the following trait must be implemented
--> /Users/rolin/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/traits/iterator.rs:55:1
|
55 | / pub trait Iterator {
56 | | /// The type of the elements being iterated over.
57 | | #[stable(feature = "rust1", since = "1.0.0")]
58 | | type Item;
... |
3457 | | }
3458 | | }
| |_^
= help: items from traits can only be used if the trait is in scope
help: the following trait is implemented but not in scope; perhaps add a `use` for it:
|
3 | use crate::diesel::ExpressionMethods;
|
error[E0599]: the method `lt` exists for struct `columns::date`, but its trait bounds were not satisfied
--> src/quant/common/persistence/database.rs:76:31
|
76 | .filter(dsl::date.lt(end_date));
| ^^ method cannot be called on `columns::date` due to unsatisfied trait bounds
|
::: src/quant/common/persistence/schema.rs:5:1
|
5 | / table! {
6 | | tb_net_worth(fund_code) {
7 | | fund_code -> VarChar,
8 | | date -> Date,
... |
12 | | }
13 | | }
| | -
| | |
| |_method `lt` not found for this
| doesn't satisfy `columns::date: Iterator`
|
= note: the following trait bounds were not satisfied:
`columns::date: Iterator`
which is required by `&mut columns::date: Iterator`
note: the following trait must be implemented
--> /Users/rolin/.rustup/toolchains/stable-x86_64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/traits/iterator.rs:55:1
|
55 | / pub trait Iterator {
56 | | /// The type of the elements being iterated over.
57 | | #[stable(feature = "rust1", since = "1.0.0")]
58 | | type Item;
... |
3457 | | }
3458 | | }
| |_^
= help: items from traits can only be used if the trait is in scope
help: the following trait is implemented but not in scope; perhaps add a `use` for it:
|
3 | use crate::diesel::ExpressionMethods;
|
error[E0599]: no method named `desc` found for struct `columns::date` in the current scope
--> src/quant/common/persistence/database.rs:80:35
|
80 | query.order(dsl::date.desc())
| ^^^^ method not found in `columns::date`
|
::: /Users/rolin/.cargo/registry/src/github.com-1ecc6299db9ec823/diesel-1.4.8/src/expression_methods/global_expression_methods.rs:397:8
|
397 | fn desc(self) -> Desc<Self> {
| ---- the method is available for `columns::date` here
|
::: src/quant/common/persistence/schema.rs:5:1
|
5 | / table! {
6 | | tb_net_worth(fund_code) {
7 | | fund_code -> VarChar,
8 | | date -> Date,
... |
12 | | }
13 | | }
| |_- method `desc` not found for this
|
= help: items from traits can only be used if the trait is in scope
help: the following trait is implemented but not in scope; perhaps add a `use` for it:
|
3 | use crate::diesel::ExpressionMethods;
|
For more information about this error, try `rustc --explain E0599`.
你能帮我解决一下吗？
错误消息包含帮助注释，可以将您推向正确的方向：
the following traits are implemented but not in scope
diesel提供的函数filter、eq、ge、lt、desc都是通过traits实现的。并且必须将特征纳入范围以供使用。您需要几个最常见的柴油特性：QueryDsl and ExpressionMethods.
所以将这些添加到您的导入中：
use diesel::expression_methods::ExpressionMethods;
use diesel::query_dsl::QueryDsl;
或者，如果您的文件非常重柴油，请考虑使用通配符导入许多柴油最常见类型的前奏：
use diesel::prelude::*;
提到 Iterator 的错误是转移注意力的错误。默认情况下，Iterator 特征总是在范围内，它具有名称匹配的函数，并且它在 &mut T 上有一个全面的实现，因为 T 是一个 Iterator.