How to work with the base in Go without specifying types?

Question

go

Hello everyone
There are functions that add/remove/update data in database tables. I work through the "ORM package" github.com/eaigner/hood.
While there are 6 tables. But I already see that 99% of the code is the same, where instead of var results []BuilderVersions you need var results []BuilderRepo
I decided to try to implement this through a universal function, but I ran into the fact that I could not get the number of results ( num : = len(num) ) invalid argument results (type interface {}) for len :

// Find Data
func (Builder *Builder) FindInDB(what string, where_string hood.Path, results interface{}) (interface{}, int, error) {
  var hd = Builder.Con.Hd
  err := hd.Where(where_string, "=", what).Find(results)
  if err != nil {
    panic(err)
  }
       //num := len(num)
  num := 1
  
  resultsret := results
  return resultsret, num, err
}


var results []BuilderRdeVersions
  fmt.Println("---1 ")
  resultsret, num, err := Builder.FindInDB("1.3", "rde_version", &results)
  fmt.Println("---2 ")
  fmt.Println("")
  fmt.Printf("resultsret %v\n", resultsret)
  fmt.Printf("num %v\n", num)
  fmt.Printf("err%v\n", err)

Result:

---1
---=
---=
tets
---2

resultsret &[{40 1.3}]
num 1
err<nil>

This is my sample function, from which I made a universal

package builder
import (
         "fmt"
        _ "github.com/eaigner/hood"
        _ "github.com/ziutek/mymysql/godrv"
        _ "io/ioutil"
        _ "os"
  _ "github.com/docopt/docopt-go"
)

type Con struct {
  jsonobject Cfgbject
  Dsn        string
  Driver     string
  Hd         *hood.Hood
  Connected  bool
  Log	bool
}

type BuilderRdeVersions struct {
  RdeId      hood.Id
  Version string `sql:"size(55)"`
}
func (Builder *Builder) AddNewVersionToDB(ver string,repository string, forceupdate bool) (err error) {
  var hd = Builder.Con.Hd
  // Find If exist
  var results []BuilderVersions
  err = hd.Where("version", "=", ver).Find(&results)
  if err != nil {
          panic(err)
  }
  n:=len(results)
  if n>0 && forceupdate==false {
    fmt.Printf("There are already exist version = %v use --force-update to udpate it \n",ver)
    return fmt.Errorf(" There are already exist version %v",ver)
  }else{
    //update - delete exist
    if n>0 {
      Builder.DeleteVersion(ver,false)
    }
    new_ver := BuilderVersions{RdeVersion:ver}
    tx := hd.Begin()
    _, err := tx.Save(&new_ver)
    if err != nil {
      panic(err)
    }
    // Commit changes
    err = tx.Commit()
    if err != nil {
      panic(err)
    }
    new_ver_path:=BuilderRepo{Repo: repository, VersionId: int64(new_ver.Id)}
          tx1:= hd.Begin()
    _, err =tx1.Save(&new_ver_path)
    err = tx1.Commit()
    if err != nil {
                  panic(err)
          }
  return nil
  }
}

Answer 1

Not sure if I understood the logic of the code, but maybe
// Find Data
func (Builder *Builder) FindInDB(what string, where_string hood.Path, results []interface{} ) (interface{}, int, error) {
var hd = Builder.Con.Hd
err := hd.Where(where_string, "=", what).Find(results)
if err != nil {
panic(err)
}
num := 1
resultsret : = results
return resultsret, num, err
}
var results []BuilderRdeVersions
fmt.Println("---1 ")
resultsret, num, err := Builder.FindInDB("1.3", "rde_version", results )
fmt.Println( "---2")
fmt.Println("")
fmt.Printf("resultsret %v\n", resultsret)
fmt.Printf("num %v\n", num)
fmt.Printf("err%v\n", err)