Golang type assertion

Question

I have created a type Role based off string, and I am now trying to get it to work with the database driver by implementing the Valuer and Scanner interfaces

Answer 1

Here is working code for the first function:

func (r *Role) Scan(value interface{}) error {
    *r = Role(value.(string))
    return nil
}

Although you may wish to use s, ok := value.(string) and return an error for !ok instead of panic-ing.

The signature for the a driver.Valuer is not what you gave but:

func (r Role) Value() (driver.Value, error) {
    return string(r), nil
}

Note this doesn't handle or produce NULL values.

Playground