Value from Row

[gusinacio]

Is it possible to get an Iterator from a Row?

I'm currently converting back every value for my own Value so I can return them as json on my http server.

[suharev7]

If you needed a convent Row in JSON, you could write something like this:

use clickhouse_rs::{
    errors::Result,
    types::{Row, SqlType, ColumnType},
};
use serde_json::{Number, Value, Map};

fn row_to_json<C>(row: &Row<'_, C>) -> Result<Value>
where
    C: ColumnType,
{
    let mut result = Map::with_capacity(row.len());
    for i in 0..row.len() {
        let value = match row.sql_type(i)? {
            SqlType::UInt32 => serde_json::Value::Number(Number::from(row.get::<u32, _>(i)?)),
            SqlType::String | SqlType::FixedString(_) => serde_json::Value::String(row.get(i)?),
            _ => todo!(),
        };
        result.insert(row.name(i)?.into(), value);
    }
    Ok(Value::Object(result))
}

or if you needed iterator:

fn row_to_iter<'a, C>(row: &'a Row<'_, C>) -> impl Iterator<Item = Result<Value>> + 'a
where
    C: ColumnType,
{
    (0..row.len()).map(|i| {
        Ok(match row.sql_type(i)? {
            SqlType::UInt32 => serde_json::Value::Number(Number::from(row.get::<u32, _>(i)?)),
            SqlType::String | SqlType::FixedString(_) => serde_json::Value::String(row.get(i)?),
            _ => todo!(),
        })
    })
}

[gusinacio]

Yeah, I'm currently doing part of this I was just wondering if the lib already had this provided. Do you think it's worth it a PR with a enum Cell which implements the FromSql trait and is a wrap for every CH type?

[suharev7]

What's the difference between enum Cell and clickhouse_rs::Value? Maybe it's better to export clickhouse_rs::Value from the crate and implement the FromSql trait for it?

[gusinacio]

That's a good one too! The current only difference between my implementation of Cell and clickhouse_rs::Value is that it has some serialization macros and also implements complex struct like String, UUID, chrono::DateTime instead of primitives.

If I use clickhouse_rs::Value, it would only work for me if I can serialize it via serde.

Do you have plans to add a feature serde within the clickhouse-rs crate?

[suharev7]

I have no plans to add serde because I don't know how to make universal serialization suitable for most applications.