private void btnBackupTables_Click(object sender, EventArgs e)
        {
            //db.BackupTableTsv("SchoolSubjects");
            //db.BackupTableTsv("TestTypes");
            //db.BackupTableTsv("QuestionTypes");
            ////db.BackupTableTsv("AnswerTypes");
            //db.BackupTableTsv("GradeTypes");
            //db.BackupTableTsv("GradeCategories");
            //db.BackupTableTsv("Schools");
            //db.BackupTableTsv("SchoolYears");
            //db.BackupTableTsv("SchoolPeriods");

            db.BackupTableXml("SchoolSubjects");
            db.BackupTableXml("TestTypes");
            db.BackupTableXml("QuestionTypes");
            //db.BackupTableXml("AnswerTypes");
            db.BackupTableXml("GradeTypes");
            db.BackupTableXml("GradeCategories");
            db.BackupTableXml("Schools");
            db.BackupTableXml("SchoolYears");
            db.BackupTableXml("SchoolPeriods");
            MessageBox.Show("Salvataggio tabelle terminato");
        }