re: https://play.golang.org/p/R5O0eSsv7H #BelajarGolang

csv2db.go

package main

import (
	"database/sql"
	"encoding/csv"
	"io"
	"log"
	"os"

	// We don't really need gorm, but it's a fast coding shorthand to throw random structs to a DB
	"github.com/jinzhu/gorm"
	_ "github.com/jinzhu/gorm/dialects/postgres"
	_ "github.com/jinzhu/gorm/dialects/sqlite"
	_ "github.com/lib/pq"
)

// Capitalized to export the fields
type testdata struct {
	Column1 string
	Column2 string
	Column3 string
	Column4 sql.NullInt64 // You wnnt this if you want real NULLs, since an int can't differentiate 0 and NULL
}

func main() {
	// Note the prevalence of "log".foo over "fmt".foo here.
	// Easier to set log to /dev/null when we're in prod, etc.
	var err error
	var wantFancyDB = true
	var db *gorm.DB

	// Either `go run main.go < test.csv` or `go run main.go test.csv`
	// No hardcoding of filenames.
	fileIn := os.Stdin
	if len(os.Args) > 1 {
		fileIn, err = os.Open(os.Args[1])
		if err != nil {
			log.Fatal(err)
		}
		defer fileIn.Close()
	}

	// Fsck it, store to db, I'm lazy, use GORM for the stuff
	if wantFancyDB {
		// This can be a "postgres", "mysql", blah as well.
		db, err = gorm.Open("sqlite3", "test.db")
		if err != nil {
			log.Fatal(db)
		}
		defer db.Close()

		// Create the tables, ensure the columns are there, etc.
		// Note that Gorm adds a "id" integer field.
		db.AutoMigrate(&testdata{})
	}

	// Create a new reader.
	reader := csv.NewReader(fileIn)

	// Let's not ignore the first line, it's good for debugging.
	headers, err := reader.Read()
	if err != nil {
		log.Fatal(err)
	}

	for {
		record, err := reader.Read()
		if err == io.EOF {
			break
		}
		if err != nil {
			log.Fatal(err)
		}

		if len(record) < 4 {
			log.Fatal("Not enough data with: ", record)
		}

		data := testdata{
			Column1: record[0],
			Column2: record[1],
			Column3: record[2],
		}
		// Meh, lazy. It's a NULL, or it's an int, or it's an error, and...
		err = data.Column4.Scan(record[3])
		if err != nil {
			// Can't parse an int, give it a NULL in db.
			data.Column4.Scan(nil)
		}

		// For your debugging pleasure:
		for k, v := range headers {
			log.Printf(" %s = %s\n", v, record[k])
		}

		// Don't bother listing the record one by one.
		log.Printf("%#v\n", data)

		// Ah, fuggit, store to db anyway
		if db != nil {
			db.NewRecord(data)
			db.Create(&data)
		}
	}
}

test.csv