A jsonb field problem about pg HOT 6 CLOSED

package main

import (
    "fmt"

    "gopkg.in/pg.v3"
)

func pgdb() *pg.DB {
    return pg.Connect(&pg.Options{
        User:     "postgres",
        Database: "test",
    })
}

func main() {
    db := pgdb()

    var user User
    _, err := db.QueryOne(&user, `SELECT '{"timezone":"mytimezone"}'::jsonb AS settings`)
    if err != nil {
        panic(err)
    }
    fmt.Printf("%#v\n", user.Settings)
}

type User struct {
    Settings *UserJsonb // it's a jsonb field in pg
}

type UserJsonb struct {
    Timezone    string
    Stockparams []float64
}

package main

import (
    "fmt"
    "time"
    "strings"
    // "database/sql/driver"
    // "encoding/json"

    "gopkg.in/pg.v3"
)

func pgdb() *pg.DB {
    return pg.Connect(&pg.Options{
        User:     "pg",
    })
}

func main() {
    db := pgdb()

    user := User{Nickname:"Leeds"}
    //if no Scan() and Value(), read from db is ok
    _, err := db.QueryOne(&user, "SELECT * FROM tbl_user WHERE LOWER(nickname) = ?", strings.ToLower(user.Nickname))
    if err != nil {
        panic(err)
    }
    fmt.Println(user.Nickname, user.Settings)

    user.Settings.Stockparams[0]++

    fmt.Println("always works well above")

    err = user.UpdateSettings() //if no Scan() and Value(), update db will panic
    if err != nil {
        fmt.Println(err.Error())
    } else {
        fmt.Println(user.Nickname, user.Settings)
    }

}

type User struct {
    Id         int
    Uid        string
    Nickname   string
    Password   string
    Salt       string
    Email      string
    Createtime time.Time
    Settings   *UserJsonb
}

func (self *User) UpdateSettings() error {
    db := pgdb()

    sql := "UPDATE tbl_user SET settings = ?settings WHERE nickname = ?nickname"
    _, err := db.ExecOne(sql, self)
    return err
}

type UserJsonb struct {
    Timezone    string
    Stockparams []float64
}

// func (m *UserJsonb) Scan(value interface{}) error {
//  return json.Unmarshal(value.([]byte), m)
// }

// func (m UserJsonb) Value() (driver.Value, error) {
//  b, err := json.Marshal(m)
//  if err != nil {
//      return nil, err
//  }
//  return string(b), nil
// }

panic: pg: unsupported src type: <main.UserJsonb Value>

goroutine 1 [running]:
gopkg.in/pg%2ev3.appendStructValue(0xc208086000, 0x24, 0x2000, 0x6518e0, 0xc20803a960, 0xd9, 0x0, 0x0, 0x0)
    /home/leeds/code/src/gopkg.in/pg.v3/append_value.go:69 +0x2a6
gopkg.in/pg%2ev3.appendValue(0xc208086000, 0x24, 0x2000, 0x6518e0, 0xc20803a960, 0xd9, 0x0, 0x0, 0x0)
    /home/leeds/code/src/gopkg.in/pg.v3/append.go:117 +0x2fd
gopkg.in/pg%2ev3.appendValue(0xc208086000, 0x24, 0x2000, 0x5d6cc0, 0xc20803a960, 0x16, 0x0, 0x0, 0x0)
    /home/leeds/code/src/gopkg.in/pg.v3/append.go:114 +0x272
gopkg.in/pg%2ev3.appendIface(0xc208086000, 0x24, 0x2000, 0x5d6cc0, 0xc20803a960, 0x0, 0x0, 0x0)
    /home/leeds/code/src/gopkg.in/pg.v3/append.go:104 +0x835
gopkg.in/pg%2ev3._appendValue(0xc208086000, 0x24, 0x2000, 0x5d6cc0, 0xc208054070, 0xd6, 0x0, 0x0, 0x0)
    /home/leeds/code/src/gopkg.in/pg.v3/types.go:25 +0xa3
gopkg.in/pg%2ev3.(*pgValue).AppendValue(0xc20802e500, 0xc208086000, 0x24, 0x2000, 0x671fa0, 0xc208054000, 0xd9, 0x0, 0x0, 0x0)
    /home/leeds/code/src/gopkg.in/pg.v3/types.go:109 +0x257
gopkg.in/pg%2ev3.formatQuery(0xc208086000, 0x24, 0x2000, 0xc20802e320, 0x43, 0x50, 0xc208077e00, 0x0, 0x1, 0x0, ...)
    /home/leeds/code/src/gopkg.in/pg.v3/append.go:399 +0x968
gopkg.in/pg%2ev3.AppendQ(0xc208086000, 0x5, 0x2000, 0x6efe90, 0x43, 0xc208077e00, 0x1, 0x1, 0x0, 0x0, ...)
    /home/leeds/code/src/gopkg.in/pg.v3/append.go:16 +0xe7
gopkg.in/pg%2ev3.writeQueryMsg(0xc20802a000, 0x6efe90, 0x43, 0xc208077e00, 0x1, 0x1, 0x0, 0x0)
    /home/leeds/code/src/gopkg.in/pg.v3/messages.go:137 +0xb8
gopkg.in/pg%2ev3.simpleQuery(0xc2080300c0, 0x6efe90, 0x43, 0xc208077e00, 0x1, 0x1, 0x10, 0x0, 0x0)
    /home/leeds/code/src/gopkg.in/pg.v3/db.go:380 +0x7f
gopkg.in/pg%2ev3.(*DB).Exec(0xc20800abb0, 0x6efe90, 0x43, 0xc208077e00, 0x1, 0x1, 0x0, 0x0, 0x0)
    /home/leeds/code/src/gopkg.in/pg.v3/db.go:195 +0xe5
gopkg.in/pg%2ev3.(*DB).ExecOne(0xc20800abb0, 0x6efe90, 0x43, 0xc208077e00, 0x1, 0x1, 0x0, 0x0, 0x0)
    /home/leeds/code/src/gopkg.in/pg.v3/db.go:208 +0x78
main.(*User).UpdateSettings(0xc208054000, 0x0, 0x0)
    /home/leeds/code/src/app/pg.go:59 +0x11e
main.main()
    /home/leeds/code/src/app/pg.go:35 +0x468

goroutine 5 [chan receive]:
github.com/golang/glog.(*loggingT).flushDaemon(0x7da280)
    /home/leeds/code/src/github.com/golang/glog/glog.go:879 +0x78
created by github.com/golang/glog.init·1
    /home/leeds/code/src/github.com/golang/glog/glog.go:410 +0x2a7

goroutine 17 [syscall, locked to thread]:
runtime.goexit()
    /usr/local/go/src/runtime/asm_amd64.s:2232 +0x1
exit status 2