特征 'rusqlite::types::to_sql::ToSql' 没有为 'serde_json::value::

Question

我正在尝试将 JSON 值从serde_json::Map序列化到 SQLite 数据库中。我想在Map中使用多种数据类型，并将它们转换为适当的SQLite数据类型。

映射在collect_values中创建并传递给write_record函数。new_db函数创建传递给write_record的rustqlite::Connection上下文

但是，当我尝试从地图中插入值时，出现此错误

error[E0277]: the trait bound `serde_json::value::Value: rusqlite::types::to_sql::ToSql` is not satisfied
--> src/main.rs:51:9
|
51 | /         params![
52 | |             &values.get("TEST-KEY-1").unwrap_or(&missing_value),
53 | |             &values.get("TEST-KEY-2").unwrap_or(&missing_value)
54 | |         ],
| |_________^ the trait `rusqlite::types::to_sql::ToSql` is not implemented for `serde_json::value::Value`
|
= note: required because of the requirements on the impl of `rusqlite::types::to_sql::ToSql` for `&serde_json::value::Value`
= note: required because of the requirements on the impl of `rusqlite::types::to_sql::ToSql` for `&&serde_json::value::Value`
= note: required for the cast to the object type `dyn rusqlite::types::to_sql::ToSql`
= note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)

是否需要手动实现序列化程序？我认为 rusqlite 的types模块已经完成了这项工作。

Cargo.toml

[package]
name = "sqlite-min-example"
version = "0.1.0"
authors = ["test"]
edition = "2018"
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[dependencies]
rusqlite = "0.23.1"
serde_json = "1.0"
serde = {version = "1.0.113", default-features = false}

main.rs

use rusqlite::{params, Connection, Result};
use serde_json::json;
use serde_json::map::Map;
fn main() {
println!("Opening connection");
let conn = new_db();
match conn {
Ok(ctx) => {
let mp = collect_values();
let res = insert_record(&mp, &ctx);
}
Err(e) => {
eprintln!("{}", e);
}
}
}
pub fn new_db() -> Result<rusqlite::Connection> {
let conn = Connection::open("test.db")?;
//let conn = Connection::open_in_memory()?;
conn.execute(
"CREATE TABLE IF NOT EXISTS testdb (
field1 INTEGER,
field2 INTEGER
)",
params![],
)?;
// return the new connection context (object)
Ok(conn)
}
pub fn insert_record(
values: &serde_json::map::Map<std::string::String, serde_json::value::Value>,
conn: &rusqlite::Connection,
) -> Result<()> {
// Insert this if we can't find a value for a key for some reason...
let missing_value = json!("MISSINGVAL");
conn.execute(
"INSERT INTO testdb 
(
field1,
field2
) 
VALUES (
?1, ?2
)",
params![
&values.get("TEST-KEY-1").unwrap_or(&missing_value),
&values.get("TEST-KEY-2").unwrap_or(&missing_value)
],
)?;
// return any errors that occured
Ok(())
}
pub fn collect_values() -> serde_json::map::Map<std::string::String, serde_json::value::Value> {
// Take in the Modbus context and return a map of keys (field names) and their associated values
let mut map = Map::new();
map.insert("TEST-KEY-1".to_string(), json!(1234));
map.insert("TEST-KEY-2".to_string(), json!(5678));
return map;
}

Answer 1

在 Cargo.toml 中为 rusqlite 添加适当的功能：

rusqlite = { version = "0.23.1", features = ["serde_json"] }

另请参阅：

• 你如何启用 Rust 的"板条箱功能"？
• 如何判断每个板条箱有哪些"功能"？