sql数据库处理函数命令

先写一个数据库统计函数

 1public static int Count(string cityName)
 2        {
 3            string cmdText = "";
 4            SqlConnection conn = new SqlConnection(DBH.DBA);
 5            SqlCommand cmd = null;
 6
 7
 8            cmdText = "Select count(*) From [Drugstore] Where CityName=@cityName ";
 9            cmd = new SqlCommand(cmdText, conn);
10            cmd.Parameters.AddWithValue("@cityName", cityName);
11            conn.Open();
12            int total = (int)cmd.ExecuteScalar();
13            conn.Close();
14            return total;
15        }
16

刚开始全部函数调用是这样一个个写出来的，后来熟悉了 用SqlHelp方便好多，在后来就直接用动软.net代码生成器了，发现对原先的这些越来越陌生了 ，现在大致整理一下，和上面重复的代码部分省略。

   1. 添加数据

 1 DrugstoreInfo info = new DrugstoreInfo();
 2     cmd.Parameters.AddWithValue("@ID",info.ID);
 3     try
 4     {
 5         conn.Open();
 6         return cmd.ExecuteNonQuery();
 7     }
 8     catch
 9     {
10         throw;
11     }
12     finally
13     {
14         conn.Close();
15     }

2.dataset 数据分页

1 public static DataSet indexQuery(int pageIndex, int pageSize)
2{
3            ..
4            SqlDataAdapter da = new SqlDataAdapter(cmd);
5            DataSet ds = new DataSet();
6            da.Fill(ds, (pageIndex - 1) * pageSize, pageSize, "Table1");
7            return ds;
8}

3. 获得最大值

 1 public static int GetMax()
 2        {
 3            string cmdText = "select Max(Id) from Application ";
 4            ..
 5            try
 6            {
 7                conn.Open();
 8                Object obj = cmd.ExecuteScalar();
 9                if (obj == null || obj is DBNull)
10                {
11                    return 1;
12                }
13                return (int)obj + 1;
14            }
15            catch
16            {
17                throw;
18            }
19            finally
20            {
21                conn.Close();
22            }
23        }

 4.  select 选择

 1public static ApplicationInfo Select(int id)
 2        {
 3            string cmdText = "select ID from Application where ID=@ID";
 4            SqlConnection conn = new SqlConnection(DBH.ConnString);
 5            SqlCommand cmd = new SqlCommand(cmdText, conn);
 6            ApplicationInfo info = new ApplicationInfo();
 7            cmd.Parameters.AddWithValue("@ID", id);
 8                conn.Open();
 9                using (IDataReader dr = cmd.ExecuteReader())
10                {
11                    if (dr.Read())
12                    {
13                        info.ID = (int)dr["ID"];
14                    }
15                    dr.Close();
16                }
17                conn.Close();
18            
19            return info;
20        }

5.delete 删除

 1 public static int Del(int id)
 2        {
 3            string cmdText = "Delete  from Application Where ID= @ID";
 4            SqlConnection conn = new SqlConnection(DBH.ConnString);
 5            SqlCommand cmd = new SqlCommand(cmdText, conn);
 6            cmd.Parameters.AddWithValue("@ID", id);
 7                conn.Open();
 8                return cmd.ExecuteNonQuery();
 9                conn.Close();
10        }

6. update 修改

 public static int Update(ApplicationInfo info)
        {
            string cmdText = "Update  Application Set City=@city Where ID=@ID";
            SqlConnection conn = new SqlConnection(DBH.ConnString);
            SqlCommand cmd = new SqlCommand(cmdText, conn);
            cmd.Parameters.AddWithValue("@ID", info.ID);
            try
            {
                conn.Open();
                return cmd.ExecuteNonQuery();
            }
            catch
            {
                throw;
            }
            finally
            {
                conn.Close();
            }
        }

 7.配置

1 public   class DBH
2    {
3        private DBH() { }
4        private static readonly string _DBA = ConfigurationManager.ConnectionStrings["DBA"].ConnectionString;
5        public static string DBA
6        {
7            get { return _DBA; }
8        }
9    }

附: configurationManager 需要命名空间 using System.Configuration 和添加引用System.Configuration 双重操作。