I try to make a Go DAL and for this i mainly used GORM.
Now I tried to make my DAL as abstract as possible, in order to be able to query many tables.
The problem is that i have to repeat myself for each table struct - reflections of my DB.
Let's get an example:
Here is two struct, one for each table in my database :
type Cad_check_status struct {
Id int
Status_code int
Last_update Timestamp
Path string
Ref_num int
System_code int
}
type Cad_check_errors struct {
Id int
check_status int
error_code Timestamp
}
And here their respective Retrieve functions (one for each, even if their are totaly the same, except for the struct instantiation which is the main problem here):
func StatusRetrieve(db *CDb, keyval map[string]interface{}) ([]byte, error){
atts := []Cad_check_status{} // <===== this is my problem, the only difference between the two functions
errors := db.Where(keyval).Find(&atts).GetErrors()
err := HandleDBErrors(errors)
if err != nil {
return nil, err
}
b, _ := json.Marshal(atts)
return b, nil
}
func ErrorsRetrieve(db *CDb, keyval map[string]interface{}) ([]byte, error){
atts := []Cad_check_errors{} // <=== my problem again, the rest is the same
errors := db.Where(keyval).Find(&atts).GetErrors()
err := HandleDBErrors(errors)
if err != nil {
return nil, err
}
b, _ := json.Marshal(atts)
return b, nil
}
So far, I tried to do something like this :
func Retrieve (tableStruct interface{}, db *CDb, keyval map[string]interface{})([]byte, error) {
atts := []tableStruct{} //<=== but of course this is IMPOSSIBLE ! but you got the idea....
errors := db.Where(keyval).Find(&atts).GetErrors()
err := HandleDBErrors(errors)
if err != nil {
return nil, err
}
b, _ := json.Marshal(atts)
return b, nil
}
Actually your last sample works just fine if you use it correctly:
func Retrieve (atts interface{}, db *CDb, keyval map[string]interface{})([]byte, error) {
errors := db.Where(keyval).Find(atts).GetErrors()
err := HandleDBErrors(errors)
if err != nil {
return nil, err
}
b, _ := json.Marshal(atts)
return b, nil
}
var values []Cad_check_status
json,err := Retrieve(&values, db, keyval)