why not use Transaction to SavePolicy about gorm-adapter HOT 6 CLOSED

// SavePolicy saves policy to database.
func (a *Adapter) SavePolicy(model model.Model) error {
	var err error
	tx := a.db.Begin()

	if a.db.Config.Name() == sqlite.DriverName {
		err = tx.Exec(fmt.Sprintf("delete from %s", a.getFullTableName())).Error
	} else {
		err = tx.Exec(fmt.Sprintf("truncate table %s", a.getFullTableName())).Error
	}

	if err != nil {
		tx.Rollback()
		return err
	}

	var lines []CasbinRule
	flushEvery := 1000
	for ptype, ast := range model["p"] {
		for _, rule := range ast.Policy {
			lines = append(lines, a.savePolicyLine(ptype, rule))
			if len(lines) > flushEvery {
				if err := tx.Create(&lines).Error; err != nil {
					tx.Rollback()
					return err
				}
				lines = nil
			}
		}
	}

	for ptype, ast := range model["g"] {
		for _, rule := range ast.Policy {
			lines = append(lines, a.savePolicyLine(ptype, rule))
			if len(lines) > flushEvery {
				if err := tx.Create(&lines).Error; err != nil {
					tx.Rollback()
					return err
				}
				lines = nil
			}
		}
	}
	if len(lines) > 0 {
		if err := tx.Create(&lines).Error; err != nil {
			tx.Rollback()
			return err
		}
	}

	tx.Commit()

	return nil
}