CRUD postgreSQL

postgres.go

/*
https://astaxie.gitbooks.io/build-web-application-with-golang/content/en/05.4.html

CREATE DATABASE "prueba" WITH ENCODING 'UTF8';
CREATE USER "santo" WITH PASSWORD 'asdfasdf';
GRANT ALL ON DATABASE "prueba" TO santo;

CREATE TABLE userinfo
(
    uid serial NOT NULL,
    username character varying(100) NOT NULL,
    departname character varying(500) NOT NULL,
    Created date,
    CONSTRAINT userinfo_pkey PRIMARY KEY (uid)
)
WITH (OIDS=FALSE);

\d+ userinfo

*/

package main

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

const (
    DB_USER     = "postgres"
    DB_PASSWORD = "asdf"
    DB_NAME     = "prueba"
)

func main() {

	//INSERT
	/***************************************************************************************/
    dbinfo := fmt.Sprintf("user=%s password=%s dbname=%s sslmode=disable",
        DB_USER, DB_PASSWORD, DB_NAME)
    db, err := sql.Open("postgres", dbinfo)
    checkErr(err)
    defer db.Close()

    fmt.Println("\n#Inserting values")

    var lastInsertId int
    err = db.QueryRow("INSERT INTO userinfo(username,departname,created) VALUES($1,$2,$3) returning uid;", 
    	"santo", "Tecnología", "2016-09-11").Scan(&lastInsertId)
    checkErr(err)
    fmt.Println("last inserted id =", lastInsertId)
    fmt.Println("\n\n\n")
    /***************************************************************************************/


    //UPDATE
    /***************************************************************************************/
    fmt.Println("# Updating")
    stmt, err := db.Prepare("UPDATE userinfo SET username=$1 WHERE uid=$2")
    checkErr(err)

    res, err := stmt.Exec("astaxieupdate", lastInsertId)
    checkErr(err)

    affect, err := res.RowsAffected()
    checkErr(err)

    fmt.Println(affect, "rows changed")
    /***************************************************************************************/


    //QUERY
    /***************************************************************************************/
    fmt.Println("# Querying")
    rows, err := db.Query("SELECT * FROM userinfo")
    checkErr(err)

    for rows.Next() {
        var uid int
        var username string
        var department string
        var created time.Time
        err = rows.Scan(&uid, &username, &department, &created)
        checkErr(err)
        //fmt.Println("uid | username | department | created ")
        fmt.Printf("%3v | %8v | %6v | %6v\n", uid, username, department, created)
    }
    /***************************************************************************************/


    //DELETE
    /***************************************************************************************/
    /*
    fmt.Println("# Deleting")
    stmt, err = db.Prepare("delete from userinfo where uid=$1")
    checkErr(err)

    res, err = stmt.Exec(lastInsertId)
    checkErr(err)

    affect, err = res.RowsAffected()
    checkErr(err)

    fmt.Println(affect, "rows changed")
    */
    /***************************************************************************************/
}

func checkErr(err error) {
    if err != nil {
        panic(err)
    }
}