private void button3_Click(object sender, EventArgs e)
{
ForeignKey f = new ForeignKey(con, comboBox1.SelectedItem.ToString(), foreign, false);
f.Show();
}
private void updateForeign_Click(object sender, EventArgs e)
{
ForeignKey f = new ForeignKey(con, comboBox1.SelectedItem.ToString(), foreign.Trim(), true);
f.Show();
}