go - Golang calling methods on interface pointer

Question

I am using Gorp for database access, Gorp has a standard DbMap type, as well as a Transaction type for when you want to be able to roll back. Both types implement the SqlExecutor interface.

I am therefore programming against the SqlExecutor interface, so I can use transactions if I want without needing to change my code.

I then initialise a Gorp DbMap or Transaction and pass it in as a field property. The problem is that I need a pointer to the Gorp "object", else how will I be able to roll back if I use a Transaction if the Gorp "object" is passed by value instead of reference.

I then get a message such as

r.Gorp.Get undefined (type *gorp.SqlExecutor has no field or method Get)

when I try use my code. How do I call the methods?

A code sample is below.

package repositories

import (
    "github.com/coopernurse/gorp"
)


type Repository struct {
    Gorp *gorp.SqlExecutor // <<<< Need pointer so I can rollback
}

func (r *Repository) GetById(i interface{}, key interface{}) interface{} {
    obj, err := r.Gorp.Get(i, key)
    if err != nil {
        panic(err)
    }
    return obj
}

Answer 1

Waitting for answers