.NET基础 （20）.NET中的数据库开发

 1 CREATE TABLE [dbo].[DepCount](
 2     [Id] [int] IDENTITY(1,1) NOT NULL,
 3     [Dep] [varchar](50) NULL,
 4     [Material] [varchar](50) NULL,
 5     [MCount] [int] NULL,
 6  CONSTRAINT [PK_DepCount] PRIMARY KEY CLUSTERED 
 7 (
 8     [Id] ASC
 9 )WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
10 ) ON [PRIMARY]
11 GO
12 SET ANSI_PADDING OFF
13 GO
14 SET IDENTITY_INSERT [dbo].[DepCount] ON
15 INSERT [dbo].[DepCount] ([Id], [Dep], [Material], [MCount]) VALUES (1, N‘产房1‘, N‘材料1‘, 1)
16 INSERT [dbo].[DepCount] ([Id], [Dep], [Material], [MCount]) VALUES (2, N‘产房2‘, N‘材料2‘, 2)
17 INSERT [dbo].[DepCount] ([Id], [Dep], [Material], [MCount]) VALUES (3, N‘产房1‘, N‘材料3‘, 1)
18 INSERT [dbo].[DepCount] ([Id], [Dep], [Material], [MCount]) VALUES (4, N‘产房3‘, N‘材料3‘, 1)
19 INSERT [dbo].[DepCount] ([Id], [Dep], [Material], [MCount]) VALUES (5, N‘产房3‘, N‘材料1‘, 1)
20 INSERT [dbo].[DepCount] ([Id], [Dep], [Material], [MCount]) VALUES (6, N‘产房1‘, N‘材料1‘, 2)
21 INSERT [dbo].[DepCount] ([Id], [Dep], [Material], [MCount]) VALUES (7, N‘产房1‘, N‘材料2‘, 1)
22 INSERT [dbo].[DepCount] ([Id], [Dep], [Material], [MCount]) VALUES (8, N‘产房1‘, N‘材料3‘, 1)
23 INSERT [dbo].[DepCount] ([Id], [Dep], [Material], [MCount]) VALUES (9, N‘产品2‘, N‘材料3‘, 1)
24 SET IDENTITY_INSERT [dbo].[DepCount] OFF

 1     partial class UseCommandBehavior
 2     {
 3         /// <summary>
 4         /// 测试方法
 5         /// </summary>
 6         /// <param name="args"></param>
 7         static void Main(string[] args)
 8         {
 9             //建立连接
10             SqlConnection con = new SqlConnection(conn_String);
11             try
12             {
13                 //测试使用了CommandBehavior.CloseConnection的方法
14                 Console.WriteLine("测试使用了CommandBehavior.CloseConnection的方法：");
15                 SqlDataReader sdr = GetReader_CloseConnection(con);
16                 while (sdr.Read()) { }
17                 sdr.Close();
18                 Console.WriteLine("读取完毕后的连接状态：" + con.State.ToString());
19                 //测试没有使用CommandBehavior.CloseConnection的方法
20                 Console.WriteLine("测试没有使用CommandBehavior.CloseConnection的方法：");
21                 SqlDataReader sdr1 = GetReader_NoCloseConnection(con);
22                 while (sdr1.Read()) { }
23                 sdr1.Close();
24                 Console.WriteLine("读取完毕后的连接状态：" + con.State.ToString());
25                 Console.Read();
26             }
27             finally
28             {
29                 //确保连接被关闭
30                 if (con.State != ConnectionState.Closed)
31                     con.Close();
32             }
33         }
34     }
35 
36     partial class UseCommandBehavior
37     {
38         const String conn_String = "Server=localhost;Integrated Security=true;database=NetTest";
39         const String Sql = "select * from dbo.DepartCost";        
40         /// <summary>
41         /// 使用CommandBehavior.CloseConnection
42         /// </summary>
43         /// <param name="con">为了测试需要，传入连接对象</param>
44         /// <returns></returns>
45         static SqlDataReader GetReader_CloseConnection(SqlConnection con)
46         {
47             try
48             {
49                 //打开连接，执行查询
50                 //并且返回SqlDataReader
51                 con.Open();
52                 SqlCommand cmd = con.CreateCommand();
53                 cmd.CommandText = Sql;
54                 SqlDataReader dr = cmd.ExecuteReader
55                                 (CommandBehavior.CloseConnection);
56                 return dr;
57             }
58             finally
59             {
60                 //因为使用了CommandBehavior.CloseConnection，
61                 //这里不需要关闭连接
62                 //con.Close();
63             }
64         }
65         /// <summary>
66         /// 不使用CommandBehavior.CloseConnection
67         /// </summary>
68         /// <param name="con">为了测试需要，传入连接对象</param>
69         /// <returns></returns>
70         static SqlDataReader GetReader_NoCloseConnection(SqlConnection con)
71         {
72             try
73             {
74                 //打开连接，执行查询
75                 //并且返回SqlDataReader
76                 con.Open();
77                 SqlCommand cmd = con.CreateCommand();
78                 cmd.CommandText = Sql;
79                 SqlDataReader dr = cmd.ExecuteReader();
80                 return dr;
81             }
82             finally
83             {
84                 //为了使返回的SqlDataReader可用，这里不能关闭连接
85                 //con.Close();
86             }
87         }
88     }

  1     /// <summary>
  2     /// 数据访问层类型
  3     /// </summary>
  4     public class DataHelper
  5     {
  6         static readonly String conn_String ="Server=localhost;Integrated Security=true;database=NetTest"; 
  7         /// <summary>
  8         /// 使用给定的sql来访问数据库
  9         /// 返回SqlDataReader对象，提供连接式访问
 10         /// </summary>
 11         /// <param name="sql">SQL命令</param>
 12         /// <returns>SqlDataReader对象</returns>
 13         public static SqlDataReader GetReader(String sql)
 14         {
 15             SqlConnection con = new SqlConnection(conn_String);
 16             try
 17             {
 18                 //打开连接，执行查询
 19                 //并且返回SqlDataReader
 20                 con.Open();
 21                 using (SqlCommand cmd = con.CreateCommand())
 22                 {
 23                     cmd.CommandText = sql;
 24                     SqlDataReader dr = cmd.ExecuteReader
 25                                     (CommandBehavior.CloseConnection);
 26                     return dr;
 27                 }
 28             }
 29             //连接数据库随时可能发生异常
 30             catch (Exception ex)
 31             {
 32                 if (con.State != ConnectionState.Closed)
 33                     con.Close();
 34                 return null;
 35             }
 36         }
 37 
 38     }
 39 
 40     /// <summary>
 41     /// 使用数据库访问层
 42     /// 连接式读取数据
 43     /// </summary>
 44     class User
 45     {
 46         //SQL命令
 47         static readonly String sql = "select * from dbo.    /// <summary>
 48     /// 数据访问层类型
 49     /// </summary>
 50     public class DataHelper
 51     {
 52         static readonly String conn_String ="Server=localhost;Integrated Security=true;database=NetTest"; 
 53         /// <summary>
 54         /// 使用给定的sql来访问数据库
 55         /// 返回SqlDataReader对象，提供连接式访问
 56         /// </summary>
 57         /// <param name="sql">SQL命令</param>
 58         /// <returns>SqlDataReader对象</returns>
 59         public static SqlDataReader GetReader(String sql)
 60         {
 61             SqlConnection con = new SqlConnection(conn_String);
 62             try
 63             {
 64                 //打开连接，执行查询
 65                 //并且返回SqlDataReader
 66                 con.Open();
 67                 using (SqlCommand cmd = con.CreateCommand())
 68                 {
 69                     cmd.CommandText = sql;
 70                     SqlDataReader dr = cmd.ExecuteReader
 71                                     (CommandBehavior.CloseConnection);
 72                     return dr;
 73                 }
 74             }
 75             //连接数据库随时可能发生异常
 76             catch (Exception ex)
 77             {
 78                 if (con.State != ConnectionState.Closed)
 79                     con.Close();
 80                 return null;
 81             }
 82         }
 83 
 84     }
 85 
 86     /// <summary>
 87     /// 使用数据库访问层
 88     /// 连接式读取数据
 89     /// </summary>
 90     class User
 91     {
 92         //SQL命令
 93         static readonly String sql = "select * from dbo.DepartCost";
 94         static void Main(string[] args)
 95         {
 96             //使用连接式方法读取数据源
 97             using (SqlDataReader reader = DataHelper.GetReader(sql))
 98             {
 99                 //得到列数
100                 int colcount = reader.FieldCount;
101                 //打印列名
102                 for (int i = 0; i < colcount; i++)
103                 {
104                     Console.Write("{0}  ", reader.GetName(i));
105                 }
106                 Console.Write("\r\n");
107                 //顺序读取每一行，并打印
108                 while (reader.Read())
109                 {
110                     for (int i = 0; i < colcount; i++)
111                     {
112                         Console.Write("{0}  ", reader[i].ToString());
113                     }
114                     Console.Write("\r\n");
115                 }
116                 reader.Close();
117             }
118             Console.Read();
119         }
120     }";
121         static void Main(string[] args)
122         {
123             //使用连接式方法读取数据源
124             using (SqlDataReader reader = DataHelper.GetReader(sql))
125             {
126                 //得到列数
127                 int colcount = reader.FieldCount;
128                 //打印列名
129                 for (int i = 0; i < colcount; i++)
130                 {
131                     Console.Write("{0}  ", reader.GetName(i));
132                 }
133                 Console.Write("\r\n");
134                 //顺序读取每一行，并打印
135                 while (reader.Read())
136                 {
137                     for (int i = 0; i < colcount; i++)
138                     {
139                         Console.Write("{0}  ", reader[i].ToString());
140                     }
141                     Console.Write("\r\n");
142                 }
143                 reader.Close();
144             }
145             Console.Read();
146         }
147     }

 1     /// <summary>
 2     /// 数据访问层类型
 3     /// </summary>
 4     public class DataHelper
 5     {
 6         static readonly String conn_String = "Server=localhost;Integrated Security=true;database=NetTest";
 7         /// <summary>
 8         /// 使用给定的sql来访问数据库
 9         /// 返回DataSet对象
10         /// </summary>
11         /// <param name="sql">SQL命令</param>
12         /// <returns>DataSet对象</returns>
13         public static DataSet GetDataSet(String sql)
14         {
15             SqlConnection con = new SqlConnection(conn_String);
16             DataSet ds = new DataSet();
17             try
18             {
19                 //打开连接，执行查询
20                 //并且返回DataSet
21                 con.Open();
22                 using (SqlDataAdapter sd = new SqlDataAdapter(sql, con))
23                 {
24                     //这里数据将被批量读入
25                     sd.Fill(ds);
26                 }
27                 return ds;
28             }
29             //连接数据库随时可能发生异常
30             catch (Exception ex)
31             {
32                 if (con.State != ConnectionState.Closed)
33                     con.Close();
34                 return ds;
35             }
36         }
37     }
38 
39     /// <summary>
40     /// 使用数据库访问层
41     /// 脱机式读取数据
42     /// </summary>
43     class User
44     {
45         //SQL命令
46         static readonly String sql = "select * from dbo.DepCount";
47         static void Main(string[] args)
48         {
49             DataSet ds = DataHelper.GetDataSet(sql);
50             //打印结果，这里假设只对DataSet中的第一个表感兴趣
51             DataTable dt = ds.Tables[0];
52             //打印列名
53             foreach (DataColumn column in dt.Columns)
54                 Console.Write("{0}  ", column.ColumnName);
55             Console.Write("\r\n");
56             //打印表
57             foreach (DataRow row in dt.Rows)
58             {
59                 for (int i = 0; i < dt.Columns.Count; i++)
60                 {
61                     Console.Write("{0}  ", row[i].ToString());
62                 }
63                 Console.Write("\r\n");
64             }
65             Console.Read();
66         }
67     }