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How to Work with Databend in Golang

Before You Begin​

Create Databend User​

mysql -h127.0.0.1 -uroot -P3307

Create a User​

mysql>
create user user1 identified by 'abc123';

Grants Privileges​

Grants ALL privileges to the user user1:

mysql>
grant all on *.* to 'user1';

Golang​

This guideline show how to connect and query to Databend using Golang. We will be creating a table named books and insert a row, then query it.

main.go​

main.go
package main

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

    _ "github.com/go-sql-driver/mysql"
)

const (
    username = "user1"
    password = "abc123"
    hostname = "127.0.0.1:3307"
)

type Book struct {
    Title   string
    Author string
    Date   string
}

func dsn() string {
    // Note Databend do not support prepared statements.
    // set interpolateParams to make placeholders (?) in calls to db.Query() and db.Exec() interpolated into a single query string with given parameters.
    // ref https://github.com/go-sql-driver/mysql#interpolateparams
    return fmt.Sprintf("%s:%s@tcp(%s)/?interpolateParams=true", username, password, hostname)
}

func main() {
    db, err := sql.Open("mysql", dsn())

    if err != nil {
        log.Fatal(err)
    }
    defer db.Close()

    err = db.Ping()
    if err != nil {
        log.Fatal(err)
    }
    log.Println("Connected")

    // Create db if do not exist
    dbSql := "create database if not exists book_db"
    _, err = db.Exec(dbSql)
    if err != nil {
        log.Fatal(err)
    }
    log.Println("Create database book_db success")

    // Use book_db database
    _, err = db.Exec("use book_db")
    if err != nil {
        log.Fatal(err)
    }

    // Create table.
    sql := "create table if not exists books(title varchar(255), author varchar(255), date varchar(255))"
    _, err = db.Exec(sql)
    if err != nil {
        log.Fatal(err)
    }
    log.Println("Create table: books")

    // Insert 1 row.
    _, err = db.Exec("insert into books values(?, ?, ?)", "mybook", "author", "2022")
    if err != nil {
        log.Fatal(err)
    }
    log.Println("Insert 1 row")

    // Select.
    res, err := db.Query("select * from books")
    if err != nil {
        log.Fatal(err)
    }

    for res.Next() {
        var book Book
        err := res.Scan(&book.Title, &book.Author, &book.Date)
        if err != nil {
            log.Fatal(err)
        }

        log.Printf("Select:%v", book)
    }

}

Golang mod​

go mod init databend-golang
go.mod
module databend-golang

go 1.18

require github.com/go-sql-driver/mysql v1.6.0

Run main.go​

go run main.go
Outputs
2022/04/13 12:20:07 Connected
2022/04/13 12:20:07 Create database book_db success
2022/04/13 12:20:07 Create table: books
2022/04/13 12:20:07 Insert 1 row
2022/04/13 12:20:08 Select:{mybook author 2022}