Golang example to insert bytes into ClickHouse as String type

clickhouse-use-string-as-bytes.go

package main

import (
    "bytes"
    "database/sql"
    "fmt"
    "log"
    "time"

    "github.com/ClickHouse/clickhouse-go"
)

func main() {
    connect, err := sql.Open("clickhouse", "tcp://127.0.0.1:9000?debug=true")
    if err != nil {
        log.Fatal(err)
    }
    if err := connect.Ping(); err != nil {
        if exception, ok := err.(*clickhouse.Exception); ok {
            fmt.Printf("[%d] %s \n%s\n", exception.Code, exception.Message, exception.StackTrace)
        } else {
            fmt.Println(err)
        }
        return
    }

    _, err = connect.Exec(`
        CREATE TABLE IF NOT EXISTS example (
            country_code String,
            os_id        UInt8,
            browser_id   UInt8,
            categories   Array(Int16),
            action_day   Date,
            action_time  DateTime
        ) engine=Memory
    `)

    if err != nil {
        log.Fatal(err)
    }
    var (
        tx, _   = connect.Begin()
        stmt, _ = tx.Prepare("INSERT INTO example (country_code, os_id, browser_id, categories, action_day, action_time) VALUES (?, ?, ?, ?, ?, ?)")
    )
    defer stmt.Close()

    // str (*bytes.Buffer) can be replace by serialized roaringbitmap
    str := bytes.NewBufferString("CN")

    for i := 0; i < 100; i++ {
        if _, err := stmt.Exec(
            //"RU",
            str.Bytes(),
            10+i,
            100+i,
            clickhouse.Array([]int16{1, 2, 3}),
            time.Now(),
            time.Now(),
        ); err != nil {
            log.Fatal(err)
        }
    }

    if err := tx.Commit(); err != nil {
        log.Fatal(err)
    }

    rows, err := connect.Query("SELECT country_code, os_id, browser_id, categories, action_day, action_time FROM example")
    if err != nil {
        log.Fatal(err)
    }
    defer rows.Close()

    for rows.Next() {
        var (
            country               string
            os, browser           uint8
            categories            []int16
            actionDay, actionTime time.Time
        )
        if err := rows.Scan(&country, &os, &browser, &categories, &actionDay, &actionTime); err != nil {
            log.Fatal(err)
        }
        log.Printf("country: %s, os: %d, browser: %d, categories: %v, action_day: %s, action_time: %s", country, os, browser, categories, actionDay, actionTime)
    }

    if err := rows.Err(); err != nil {
        log.Fatal(err)
    }

    if _, err := connect.Exec("DROP TABLE example"); err != nil {
        log.Fatal(err)
    }
}