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use serde::{Deserialize, Serialize};
use clickhouse::sql::Identifier;
use clickhouse::{Client, Row, error::Result};
// See also: https://clickhouse.com/docs/en/sql-reference/data-types/variant
#[tokio::main]
async fn main() -> Result<()> {
let table_name = "chrs_data_types_variant";
let client = Client::default().with_url("http://localhost:8123");
// No matter the order of the definition on the Variant types in the DDL, this particular Variant will always be sorted as follows:
// Variant(Array(UInt16), Bool, FixedString(6), Float32, Float64, Int128, Int16, Int32, Int64, Int8, String, UInt128, UInt16, UInt32, UInt64, UInt8)
client
.query(
"
CREATE OR REPLACE TABLE ?
(
`id` UInt64,
`var` Variant(
Array(UInt16),
Bool,
Date,
FixedString(6),
Float32, Float64,
Int128, Int16, Int32, Int64, Int8,
String,
UInt128, UInt16, UInt32, UInt64, UInt8
)
)
ENGINE = MergeTree
ORDER BY id",
)
.bind(Identifier(table_name))
.with_setting("allow_experimental_variant_type", "1")
// This is required only if we are mixing similar types in the Variant definition
// In this case, this is various Int/UInt types, Float32/Float64, and String/FixedString
// Omit this setting if there are no similar types in the definition
.with_setting("allow_suspicious_variant_types", "1")
.execute()
.await?;
let mut insert = client.insert::<MyRow>(table_name).await?;
let rows_to_insert = get_rows();
for row in rows_to_insert {
insert.write(&row).await?;
}
insert.end().await?;
let rows = client
.query("SELECT ?fields FROM ?")
.bind(Identifier(table_name))
.fetch_all::<MyRow>()
.await?;
println!("{rows:#?}");
Ok(())
}
fn get_rows() -> Vec<MyRow> {
vec![
MyRow {
id: 1,
var: MyRowVariant::Array(vec![1, 2]),
},
MyRow {
id: 2,
var: MyRowVariant::Boolean(true),
},
MyRow {
id: 3,
var: MyRowVariant::Date(
time::Date::from_calendar_date(2021, time::Month::January, 1).unwrap(),
),
},
MyRow {
id: 4,
var: MyRowVariant::FixedString(*b"foobar"),
},
MyRow {
id: 5,
var: MyRowVariant::Float32(100.5),
},
MyRow {
id: 6,
var: MyRowVariant::Float64(200.1),
},
MyRow {
id: 7,
var: MyRowVariant::Int8(2),
},
MyRow {
id: 8,
var: MyRowVariant::Int16(3),
},
MyRow {
id: 9,
var: MyRowVariant::Int32(4),
},
MyRow {
id: 10,
var: MyRowVariant::Int64(5),
},
MyRow {
id: 11,
var: MyRowVariant::Int128(6),
},
MyRow {
id: 12,
var: MyRowVariant::String("my_string".to_string()),
},
MyRow {
id: 13,
var: MyRowVariant::UInt8(7),
},
MyRow {
id: 14,
var: MyRowVariant::UInt16(8),
},
MyRow {
id: 15,
var: MyRowVariant::UInt32(9),
},
MyRow {
id: 16,
var: MyRowVariant::UInt64(10),
},
MyRow {
id: 17,
var: MyRowVariant::UInt128(11),
},
]
}
// As the inner Variant types are _always_ sorted alphabetically,
// Rust enum variants should be defined in the _exactly_ same order as it is in the data type;
// their names are irrelevant, only the order of the types matters.
// This enum represents Variant(Array(UInt16), Bool, Date, FixedString(6), Float32, Float64, Int128, Int16, Int32, Int64, Int8, String, UInt128, UInt16, UInt32, UInt64, UInt8)
#[derive(Debug, PartialEq, Serialize, Deserialize)]
enum MyRowVariant {
Array(Vec<u16>),
Boolean(bool),
// attributes should work in this case, too
#[serde(with = "clickhouse::serde::time::date")]
Date(time::Date),
// NB: by default, fetched as raw bytes
FixedString([u8; 6]),
Float32(f32),
Float64(f64),
Int128(i128),
Int16(i16),
Int32(i32),
Int64(i64),
Int8(i8),
String(String),
UInt128(u128),
UInt16(i16),
UInt32(u32),
UInt64(u64),
UInt8(i8),
}
#[derive(Debug, PartialEq, Row, Serialize, Deserialize)]
struct MyRow {
id: u64,
var: MyRowVariant,
}