C#通用数据访问类：一

 1         private static string connString = ConfigurationManager.ConnectionStrings["connString"].ToString(); 
 2 
 3         /// <summary>
 4         /// 执行增、删、改操作
 5         /// </summary>
 6         /// <param name="sql">SQL语句</param>
 7         /// <returns></returns>
 8         public int Update(string sql)
 9         {
10             SqlConnection sqlConnection = new SqlConnection(connString);
11             SqlCommand sqlCommand = new SqlCommand(sql, sqlConnection);
12             try
13             {
14                 sqlConnection.Open();
15                 return sqlCommand.ExecuteNonQuery();
16             }
17             catch (Exception ex)
18             {
19                 string errorinfo = "调用public int Update(string sql)方法时发生错误" + ex.Message;
20                 WriteLog(errorinfo);
21                 throw new Exception(errorinfo);
22             }
23             finally
24             {
25                 sqlConnection.Close();
26             }
27         }