added 23503 pgerrcode support and updated the error conversion approa…

…ch (#185)

* added 23503 pgerrcode support and updated the error conversion approach

* updated to meaningful variables names

error_translator.go

@@ -6,8 +6,9 @@ import (
 	"gorm.io/gorm"
 )
 
-var errCodes = map[string]string{
-	"uniqueConstraint": "23505",
+var errDesToGormErrs = map[string]error{
+	"23505": gorm.ErrDuplicatedKey,
+	"23503": gorm.ErrForeignKeyViolated,
 }
 
 type ErrMessage struct {
@@ -20,8 +21,9 @@ type ErrMessage struct {
 // Since currently gorm supporting both pgx and pg drivers, only checking for pgx PgError types is not enough for translating errors, so we have additional error json marshal fallback.
 func (dialector Dialector) Translate(err error) error {
 	if pgErr, ok := err.(*pgconn.PgError); ok {
-		if pgErr.Code == errCodes["uniqueConstraint"] {
-			return gorm.ErrDuplicatedKey
+		gormErr, ok := errDesToGormErrs[pgErr.Code]
+		if ok {
+			return gormErr
 		}
 		return err
 	}