Decimal | ScyllaDB Docs

Decimal¶

Decimal is represented as value::CqlDecimal or bigdecimal::BigDecimal

value::CqlDecimal¶

Without any feature flags, the user can interact with decimal type by making use of value::CqlDecimal or value::CqlDecimalBorrowed which are very simple wrappers representing the value as signed binary number in big-endian order with a 32-bit scale.

use futures::TryStreamExt;
use scylla::frame::value::CqlDecimal;
use std::str::FromStr;

// Insert a decimal (123.456) into the table
let to_insert: CqlDecimal =
        CqlDecimal::from_signed_be_bytes_and_exponent(vec![0x01, 0xE2, 0x40], 3);
session
    .query_unpaged("INSERT INTO keyspace.table (a) VALUES(?)", (to_insert,))
    .await?;

// Read a decimal from the table
let mut iter = session.query_iter("SELECT a FROM keyspace.table", &[])
    .await?
    .rows_stream::<(CqlDecimal,)>()?;
while let Some((decimal_value,)) = iter.try_next().await? {
    println!("{:?}", decimal_value);
}

bigdecimal::BigDecimal¶

To make use of bigdecimal::Bigdecimal type, user should enable bigdecimal-04 crate feature.

use futures::TryStreamExt;
use bigdecimal::BigDecimal;
use std::str::FromStr;

// Insert a decimal into the table
let to_insert: BigDecimal = BigDecimal::from_str("12345.0")?;
session
    .query_unpaged("INSERT INTO keyspace.table (a) VALUES(?)", (to_insert,))
    .await?;

// Read a decimal from the table
let mut iter = session.query_iter("SELECT a FROM keyspace.table", &[])
    .await?
    .rows_stream::<(BigDecimal,)>()?;
while let Some((decimal_value,)) = iter.try_next().await? {
    println!("{:?}", decimal_value);
}

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