Go Scanner仍然返回<nil>

Question

first of all: I am totally newbie in golang, so I may not understand well. I am tasked to write a Go data extractor from one database using "gorp". The problem is with one table, that has custom field "TimeRange". It is defined as:

type TimeRange struct {
    From string
    To  string
}

Sadly when I try to fetch row I am getting scanner error, so I realised I need a custom scanner.

// Scan - Implement the database/sql scanner interface
func (tr *TimeRange) Scan(value interface{}) error {
    tr.From = "mis"
    tr.To = "lala"
    fmt.Printf("%v
", *tr)

    return nil
}

So I expect to see fixed '{mis lala}' in returned string. Why I am getting:

var q2 []models.Dashboard
result, err := dbmap.Select(&q2, "select * from dashboard where id=3")
fmt.Printf("q2=%v
", q2)

prints:

p2=[{{<nil> Tomek b1f6f0ba-f618-00d6-6d24-8410a9219c95}}]

which is: TimeRange, UserName and UUID

Might be important: using "gorp" for DB managment

Answer 1

the scan function would be called on passed value type to dbmap.Select() so in your case, you need to implement Dashboard as scanner.