Go: gorm で PostgreSQL のデータを作成 (Create)

プログラム

フォルダー構造

$ tree -a
.
├── .env
├── config_postgres.go
└─── gorm_pg_create.go

gorm_pg_create.go

// ----------------------------------------------------------------
//
//	gorm_pg_create.go
//
//					Mar/03/2023
//
// ----------------------------------------------------------------
package main

import (
	"fmt"
	"os"
	"gorm.io/gorm"
	"gorm.io/driver/postgres"
)

// ----------------------------------------------------------------
func unit_gen_proc (name string,population int,date_mod string) map[string]interface{} {
	unit_aa := make (map[string]interface{})
	unit_aa["name"] = name
	unit_aa["population"] = population
	unit_aa["date_mod"] = date_mod

	return (unit_aa)
}

// ----------------------------------------------------------------
func data_prepare_proc () map[string](map[string]interface{}) {
	dict_aa := make (map[string](map[string]interface{}))

	dict_aa["t3461"] = unit_gen_proc ("広島",37452,"1921-11-11")
	dict_aa["t3462"] = unit_gen_proc ("福山",89271,"1921-8-25")
	dict_aa["t3463"] = unit_gen_proc ("東広島",63597,"1921-4-14")
	dict_aa["t3464"] = unit_gen_proc ("呉",95178,"1921-2-20")
	dict_aa["t3465"] = unit_gen_proc ("尾道",41749,"1921-6-24")
	dict_aa["t3466"] = unit_gen_proc ("竹原",74582,"1921-1-10")
	dict_aa["t3467"] = unit_gen_proc ("三次",48297,"1921-10-19")
	dict_aa["t3468"] = unit_gen_proc ("大竹",38591,"1921-12-28")
	dict_aa["t3469"] = unit_gen_proc ("府中",25978,"1921-5-14")

	return (dict_aa)
}

// ----------------------------------------------------------------
func main() {
	fmt.Fprintln (os.Stderr,"*** 開始 ***")

	dict_aa := data_prepare_proc ()

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

dsn := "host=" + host + " user=" + user + " password=" + password + " dbname=" + data_base + " port=5432 sslmode=disable TimeZone=Asia/Tokyo"

	db, err := gorm.Open(postgres.Open(dsn), &gorm.Config{})
	if err != nil {
		panic(err)
		}

	db.Exec ("drop table cities")

	sql_str := "create table cities (id varchar(10),name varchar(20),population int,date_mod date)"
	fmt.Println (sql_str)

	db.Exec (sql_str)

	for key,_ := range dict_aa {
		name := dict_aa[key]["name"]
		population := dict_aa[key]["population"]
		date_mod := dict_aa[key]["date_mod"]
		sql_str :="insert into cities (id,name,population,date_mod) values (?,?,?,?)"
		db.Exec (sql_str,key,name,population,date_mod)
		}

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

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

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

実行の準備

go mod init create
go mod tidy

go.mod go.sum が作成される。

実行結果

$ go run gorm_pg_create.go config_postgres.go
*** 開始 ***
create table cities (id varchar(10),name varchar(20),population int,date_mod date)
*** 終了 ***

確認したバージョン

$ go version
go version go1.22.2 linux/amd64