Go言語でDB操作

01 golangdb.go

package main

import (
        "database/sql"
        "fmt"
        _ "github.com/lib/pq"
)

var Db *sql.DB

func init() {
        var err error
        // DB名やユーザー、テーブルは適宜適切な値を入れてください
        Db, err = sql.Open("postgres", "user=gwp dbname=postgres password=gwp sslmode=disable")
        if err != nil {
                panic(err)
        }
}

type Member struct {
        Id         int
        FirstName  string
        LastName   string
        Email      string
        AccessPrev bool
}

func main() {
        fmt.Println("----- Query 1 -----")
        rows, err := Db.Query("SELECT * FROM members ORDER BY id")
        if err != nil {
                return
        }
        for rows.Next() {
                m := Member{}
                rows.Scan(&m.Id, &m.FirstName, &m.LastName, &m.Email, &m.AccessPrev)
                fmt.Println(m)
        }
        fmt.Println()

        fmt.Println("----- Query 2 -----")
        rows, err = Db.Query("SELECT * FROM members WHERE accessprev = $1 ORDER BY id", "false")
        if err != nil {
                return
        }
        for rows.Next() {
                m := Member{}
                rows.Scan(&m.Id, &m.FirstName, &m.LastName, &m.Email, &m.AccessPrev)
                fmt.Println(m)
        }
        fmt.Println()

        fmt.Println("----- QueryRow -----")
        m := Member{}
        err = Db.QueryRow("SELECT * FROM members WHERE accessprev = $1 ORDER BY id", "true").Scan(&m.Id, &m.FirstName, &m.LastName, &m.Email, &m.AccessPrev)
        if err != nil {
                return
        }
        fmt.Println(m)
        fmt.Println()

        fmt.Println("----- Prepare -----")
        statement := "SELECT * FROM members WHERE accessprev = $1 ORDER BY id"
        stmt, err := Db.Prepare(statement)
        if err != nil {
                return
        }
        defer stmt.Close()

        rows, err = stmt.Query("false")
        for rows.Next() {
                m := Member{}
                rows.Scan(&m.Id, &m.FirstName, &m.LastName, &m.Email, &m.AccessPrev)
                fmt.Println(m)
        }
        fmt.Println()

        fmt.Println("----- Exec -----")
        _, err = Db.Exec("INSERT INTO members VALUES ($1, $2, $3, $4, $5)", 4, "takashi", "yamamoto", "yamamoto@yahoo.co.jp", "FALSE")
        if err != nil {
                return
        }
        rows, err = Db.Query("SELECT * FROM members ORDER BY id")
        if err != nil {
                return
        }
        for rows.Next() {
                m := Member{}
                rows.Scan(&m.Id, &m.FirstName, &m.LastName, &m.Email, &m.AccessPrev)
                fmt.Println(m)
        }
        fmt.Println()

}

02 result

----- Query 1 -----
{1 minoru tanaka tanaka@gmail.com true}
{2 tadashi sato sato@gmail.com false}
{3 sachiko suzuki suzuki@yahoo.co.jp false}

----- Query 2 -----
{2 tadashi sato sato@gmail.com false}
{3 sachiko suzuki suzuki@yahoo.co.jp false}

----- QueryRow -----
{1 minoru tanaka tanaka@gmail.com true}

----- Prepare -----
{2 tadashi sato sato@gmail.com false}
{3 sachiko suzuki suzuki@yahoo.co.jp false}

----- Exec -----
{1 minoru tanaka tanaka@gmail.com true}
{2 tadashi sato sato@gmail.com false}
{3 sachiko suzuki suzuki@yahoo.co.jp false}
{4 takashi yamamoto yamamoto@yahoo.co.jp false}