DuckDB to Rust type mapping reference in better-duck

diesel::table! {
    use diesel::sql_types::*;
    use better_duck_diesel::sql_types::*;

    readings (id) {
        id      -> Integer,
        sensor  -> DuckEnum,         // DuckDB ENUM column
        value   -> Double,
        ts      -> DuckTimestamptz,  // TIMESTAMPTZ column
        tags    -> DuckList,         // LIST column
    }
}

pub trait AppendAble {
    /// Binds this value to a prepared statement parameter.
    /// `idx` is **1-based** — the first parameter is `idx = 1`.
    fn stmt_append(&mut self, idx: u64, stmt: duckdb_prepared_statement) -> Result<()>;

    /// Appends this value to an appender row.
    fn appender_append(&mut self, appender: duckdb_appender) -> Result<()>;
}

use better_duck_core::types::appendable::AppendAble;
use better_duck_core::ffi::{duckdb_appender, duckdb_prepared_statement, duckdb_append_int32, duckdb_bind_int32};
use better_duck_core::error::Result;

struct IntRow(i32);

impl AppendAble for IntRow {
    fn appender_append(&mut self, appender: duckdb_appender) -> Result<()> {
        // SAFETY: appender is valid; the table has one INTEGER column.
        unsafe { duckdb_append_int32(appender, self.0) };
        Ok(())
    }
    fn stmt_append(&mut self, idx: u64, stmt: duckdb_prepared_statement) -> Result<()> {
        // SAFETY: stmt is valid; idx is a 1-based parameter index.
        unsafe { duckdb_bind_int32(stmt, idx, self.0) };
        Ok(())
    }
}