package main

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

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

type MyType string

func (self MyType) Value() (v driver.Value, err error) {
	return strings.ToUpper(string(self)), nil
}

func main() {
	db, err := sql.Open("postgres", "dbname=test sslmode=disable")
	E(err)
	_, err = db.Exec("drop table if exists a")
	E(err)
	_, err = db.Exec("create table a(id bigserial primary key, t text)")

	q := "insert into a(t) values($1)"

	// Works with value
	s := "one"
	_, err = db.Exec(q, s)
	E(err)

	// Works with pointer
	var ps *string
	s = "two"
	ps = &s
	_, err = db.Exec(q, ps)
	E(err)

	// Works with nil pointer
	ps = nil
	_, err = db.Exec(q, ps)
	E(err)

	// Works with value
	v := MyType("four")
	_, err = db.Exec(q, v)
	E(err)

	// Works with pointer
	v = MyType("five")
	pv := &v
	_, err = db.Exec(q, pv)
	E(err)

	// Does NOT work with nil pointer
	pv = nil
	_, err = db.Exec(q, pv)
	E(err)
}