第 0002 題：將 0001 題生成的 200 個(gè)激活碼（或者優(yōu)惠券）保存到 MySQL 關(guān)系型數(shù)據(jù)庫(kù)中。

1. 創(chuàng)建優(yōu)惠券表

mysql> create table promotion_code (
    -> promotion_code varchar(255),
    -> used bool,
    -> );

2. 生成優(yōu)惠碼(golang學(xué)習(xí)---練習(xí)1)
3. 將生成的優(yōu)惠碼存入，mysql

package main
import (
    "database/sql"
    "fmt"
    _ "github.com/go-sql-driver/mysql"
    "log"
    "time"
    "math/rand"
    "encoding/base64"
)

func main() {

    codes := generate_code()
    fmt.Println(codes)
    db, err := sql.Open("mysql", "mysql:123456@/gotest?charset=utf8")
    defer db.Close()
    if err != nil {
        log.Fatal(err)
    }

    for _, code := range codes  {
        stmt, err := db.Prepare("insert into promotion_code (promotion_code, used) values (?, ?)")
        if err != nil {
            log.Fatal(err)
        }

        _, err = stmt.Exec(code, false)
        if err != nil {
            log.Println(err)
        }
    }


}
/*
生成優(yōu)惠碼
*/
func generate_code() []string {
    var codes []string
    for i := 0; i < 200; i++ {
        //
        randNum := rand.Int()
        //獲取納秒
        t := time.Now().UnixNano()
        result := fmt.Sprint(randNum) + fmt.Sprint(t)
        encoded := base64.StdEncoding.EncodeToString([]byte(result))
        codes = append(codes, encoded)
    }
    return codes
}