Go: gorm で MariaDB のデータを更新 (Update)

プログラム

フォルダー構造

$ tree -a
.
├── .env
├── config_mariadb.go
├── go.mod
├── go.sum
└── gorm_update.go

gorm_update.go

// ----------------------------------------------------------------
//
//	gorm_update.go
//
//					Feb/27/2023
//
// ----------------------------------------------------------------
package main

import (
	"fmt"
	"os"
	"strconv"
	"time"
	"gorm.io/gorm"
	"gorm.io/driver/mysql"
)

// ----------------------------------------------------------------
func main() {
	fmt.Fprintln (os.Stderr,"*** 開始 ***")
	key_in := os.Args[1]
	population_in,_ := strconv.Atoi (os.Args[2])

	fmt.Printf ("key_in = %s\t" , key_in)
	fmt.Printf ("population_in = %d\n" , population_in)

	host,user,password,data_base := config_mariadb_proc()

	dsn := user + ":" + password + "@tcp(" + host + ":3306)/" + data_base + "?charset=utf8mb4&parseTime=True&loc=Local"
	db, err := gorm.Open(mysql.Open(dsn), &gorm.Config{})
	if err != nil {
		panic(err)
	}

	today := get_current_date_proc ()

	fmt.Println (today)

	db.Exec("UPDATE cities SET population = ?,date_mod = ? WHERE id = ?", population_in,today,key_in)

	fmt.Fprintln (os.Stderr,"*** 終了 ***")
}

// ----------------------------------------------------------------
func get_current_date_proc () string {
	now := time.Now ()
	fmt.Printf ("%s\t" ,now)
	fmt.Printf ("%d-%d-%d\n" ,now.Year (),now.Month(),now.Day())
	today := strconv.Itoa (now.Year()) + "-" +
		fmt.Sprintf ("%d",now.Month()) + "-" +
		strconv.Itoa (now.Day())

	return	today
}

// ----------------------------------------------------------------

.env
config_mariadb.go
はこちら
Go: gorm で MariaDB のバージョンを表示

実行の準備

go mod init update
go mod tidy

実行

go run gorm_update.go config_mariadb.go t3328 892453100

確認したバージョン

$ go version
go version go1.20.1 linux/amd64