klickhouse 0.15.3

Klickhouse is a pure Rust SDK for working with Clickhouse with the native protocol in async environments with minimal boilerplate and maximal performance.
Documentation 
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use std::borrow::Cow;

use crate::{FromSql, KlickhouseError, Result, Row, ToSql, Type, Value};

/// A single column row
#[derive(Clone, Debug, Default)]
pub struct UnitValue<T: FromSql + ToSql>(pub T);

impl<T: FromSql + ToSql> Row for UnitValue<T> {
    const COLUMN_COUNT: Option<usize> = Some(1);

    fn column_names() -> Option<Vec<Cow<'static, str>>> {
        None
    }

    fn deserialize_row(map: Vec<(&str, &Type, Value)>) -> Result<Self> {
        if map.is_empty() {
            return Err(KlickhouseError::MissingField("<unit>"));
        }
        let item = map.into_iter().next().unwrap();
        T::from_sql(item.1, item.2).map(UnitValue)
    }

    fn serialize_row(
        self,
        type_hints: &indexmap::IndexMap<String, Type>,
    ) -> Result<Vec<(Cow<'static, str>, Value)>> {
        Ok(vec![(
            Cow::Borrowed("_"),
            self.0.to_sql(type_hints.values().next())?,
        )])
    }
}