libfic: add new functions to retrieve the Id of some contents from Title, Label, ...

libfic/flag_key.go

@@ -127,6 +127,15 @@ func (k FlagKey) GetId() int64 {
 	return k.Id
 }
 
+// RecoverId returns the Flag identifier as register in DB.
+func (k FlagKey) RecoverId() (Flag, error) {
+	if err := DBQueryRow("SELECT id_flag FROM exercice_flags WHERE type LIKE ? AND id_exercice = ?", k.Label, k.IdExercice).Scan(&k.Id); err != nil {
+		return FlagKey{}, err
+	} else {
+		return k, err
+	}
+}
+
 // AddFlagKey creates and fills a new struct Flag, from a hashed flag, and registers it into the database.
 func (k FlagKey) Create(e Exercice) (Flag, error) {
 	// Check the regexp compile