//click event to delete an existing employee
        private void deleteEmpButton_Click(object sender, EventArgs e)
        {
            string firstName = firstNameTextBox.Text;
            string email     = emailTextBox.Text;

            bool response = Operations.DeleteEmployee(firstName, email);

            if (response == true)
            {
                MessageBox.Show("Employee deleted!");
                firstNameTextBox.Text   = "";
                lastNameTextBox.Text    = "";
                emailTextBox.Text       = "";
                phoneNumberTextBox.Text = "";
                salaryTextBox.Text      = "";
                deptIdTextBox.Text      = "";
            }
            else
            {
                MessageBox.Show("Operation Failed!");
            }
        }