golang reflect into []interface{} - go

Question

i wanna create a mini framework which takes a simple struct and creates a full crud out of it. i already started and the "findOne, update,create,delete" is working. not i have a problem to create a findAll method. to be more clear, i dont know how to use reflect to address my ptr to an array of struct.
Here a small example for the findOne function.
type company struct {
Id int
Name string
}
comp.InitModel(newDbConnection(), &comp)
In InitModel i can fill the pointer to the company with the following:
//m.caller = pointer to the ptr to comp (struct)
callerV := reflect.ValueOf(m.caller)
CallerField := callerV.Elem()
var values []interface{}
for _, e := range m.columns {
values = append(values, CallerField.FieldByName(e.name).Addr().Interface())
}
err := r.Scan(values...)
if err != nil {
return err
}
Now i wanna create a findAll method which would be called like this
var companies []company
comp.InitModel(newDbConnection(), &comp)
comp.FindAll(&companies) //in this is the db query and scan
fmt.Println(companies) //here should be the result
But i have a problem to get the reflect with a []interface working.
func (m *Model) FindAll(test []interface{}, c *Condition) error {
//get the sql statement from the struct
stmt := PrepairStmt(m, c)
rows, err := m.db.Query(stmt.selectParse(), c.arguments...)
if err != nil {
return err
}
defer rows.Close()
callerV := reflect.ValueOf(m.caller)
CallerField := callerV.Elem()
for rows.Next() {
var values []interface{}
for _, e := range m.columns {
values = append(values, CallerField.FieldByName(e.name).Addr().Interface())
}
err = rows.Scan(values...)
if err != nil {
return err
}
valuePtr := reflect.New(reflect.TypeOf(test).Elem())
test = reflect.Append(test,reflect.ValueOf(values))
}
return nil
}
Thats were my latest tries.
maybe someone can help me with this.
i would be really thankful

Answer 1

Use interface{} instead of []interface{} as the argument type:
func (m *Model) FindAll(result interface{}, c *Condition) error {
stmt := PrepairStmt(m, c)
rows, err := m.db.Query(stmt.selectParse(), c.arguments...)
if err != nil {
return err
}
defer rows.Close()
// resultv is the result slice
resultv := reflect.ValueOf(result).Elem()
// rowt is the struct type
rowt := resultv.Type().Elem()
// allocate a value for the row
rowv := reflect.New(rowt).Elem()
// collect values for scan
var values []interface{}
for _, e := range m.columns {
values = append(values, rowv.FieldByName(e.name).Addr().Interface())
}
for rows.Next() {
err = rows.Scan(values...)
if err != nil {
return err
}
// Append struct to result slice. Because the struct
// is copied in append, we can reuse the struct in
// this loop.
resultv.Set(reflect.Append(resultv, rowv))
}
return nil
}
Use it like this:
var companies []company
comp.InitModel(newDbConnection(), &comp)
comp.FindAll(&companies) //in this is the db query and scan