Macro named_params 

macro_rules! named_params {
    ($($name:literal : $param:expr),* $(,)?) => { ... };
}

Convenience macro to build a named parameter slice.

This coerces each value to &dyn ToSql, which is useful when named parameters have different Rust types. Parameter names must be bare names without the $ prefix. This differs from rusqlite-style named parameter slices, where keys commonly include the placeholder prefix. This macro must be used with named SQL placeholders such as $name, not positional placeholders such as ? or ?1.

Example

fn find(conn: &Connection, min_age: i32, name: &str) -> Result<bool> {
    conn.query_row(
        "SELECT $age >= 18 AND $name = 'Alice'",
        named_params! {
            "age": min_age,
            "name": name,
        },
        |row| row.get(0),
    )
}