/// <summary>
///执行SQL语句
/// </summary>
/// <param name="str">SQL语句</param>
public static void non(string str)
{
SqlConnection sql = CourseSys.sql();
SqlCommand cmd = new SqlCommand(str, sql);
cmd.ExecuteNonQuery();
sql.Close();
}
/// <summary>
/// 返回DataTable集
/// </summary>
/// <param name="str">SQL语句</param>
/// <returns></returns>
public static DataTable gettb(string str)
{
SqlConnection sql = CourseSys.sql();
SqlDataAdapter sda = new SqlDataAdapter(str, sql);
DataSet dbds = new DataSet();
sda.Fill(dbds);
sql.Close();
return(dbds.Tables[0]);
}