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Varint¶
Varint is represented as value::CqlVarint or num_bigint::BigInt.
num_bigint::BigInt¶
To make use of num_bigint::BigInt type, user should enable one of the available feature flags (num-bigint-03 or num-bigint-04). They enable support for num_bigint::BigInt v0.3 and v0.4 accordingly.
value::CqlVarint¶
Without any feature flags, the user can interact with Varint type by making use of value::CqlVarint or value::CqlVarintBorrowed which are very simple wrappers representing the value as signed binary number in big-endian order.
Example¶
use futures::TryStreamExt;
use num_bigint::BigInt;
use std::str::FromStr;
// Insert a varint into the table
let to_insert: BigInt = BigInt::from_str("12345")?;
session
.query_unpaged("INSERT INTO keyspace.table (a) VALUES(?)", (to_insert,))
.await?;
// Read a varint from the table
let mut iter = session.query_iter("SELECT a FROM keyspace.table", &[])
.await?
.rows_stream::<(BigInt,)>()?;
while let Some((varint_value,)) = iter.try_next().await? {
println!("{:?}", varint_value);
}