数据访问----实例1

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6 using System.Data;
 7 using System.Data.SqlClient;
 8 
 9 namespace yy
10 {
11     class Program
12     {
13         public static void Login()
14         {
15             Console.Write("请输入账号：");
16             string name = Console.ReadLine();
17             Console.Write("请输入密码：");
18             string password = Console.ReadLine();
19             SqlConnection lcon = new SqlConnection("server=.;database=xx;uid=sa;pwd=111111");
20             lcon.Open();
21 
22             SqlCommand lcmd = lcon.CreateCommand();
23             lcmd.CommandText = "select * from Login where Uid='"+name+"' and Pwd='"+password+"'";
24             SqlDataReader re=lcmd.ExecuteReader();
25             if (re.HasRows){
26                 Console.Write("登录成功！"); }
27             else {
28                 Console.Write("账号或密码输入不正确！"); 
29             }
30 
31             lcon.Close();
32 
33         }
34         public static void _Stu()
35         {
36             Console.WriteLine("**************************操作记录***************************");
37             Console.WriteLine("请选择：0：增加记录 1：修改记录 2：删除记录 3:读取所有记录 4:读取记录");
38             string xz = Console.ReadLine();
39             switch (xz)
40             {
41                 case "0": yy.Class1.create();
42                     break;
43                 case "1": yy.Class1.updateBysid();
44                     break;
45                 case "2": yy.Class1.deleteBysid();
46                     break;
47                 case "3": yy.Class1.Read();
48                     break;
49                 case "4": yy.Class1.Cha();
50                     break;
51                 default:
52                     Console.WriteLine("输入有误！！");
53                     break;
54             }
55 
56         }
57       
58         static void Main(string[] args)
59         {
60 
61            // Login();
62 
63             _Stu();
64            
65             
66             Main(args);
67 
68         }
69 
70     }
71 }
  1 using System;
  2 using System.Collections.Generic;
  3 using System.Linq;
  4 using System.Text;
  5 using System.Threading.Tasks;
  6 using System.Data;
  7 using System.Data.SqlClient;
  8 namespace yy
  9 {
 10     class Class1
 11     {
 12         public static void create()
 13         {
 14             Console.WriteLine("**************************增加记录***************************");
 15             Console.Write("学号：");
 16             string sid = Console.ReadLine();
 17             Console.Write("姓名：");
 18             string sname = Console.ReadLine();
 19             Console.Write("性别：");
 20             string ssex = Console.ReadLine();
 21             Console.Write("班级：");
 22             string sclass = Console.ReadLine();
 23 
 24             SqlConnection scon = new SqlConnection("server=.;database=xx;uid=sa;pwd=111111");
 25             scon.Open();
 26             SqlCommand scmd = new SqlCommand();
 27             scmd.Connection = scon;
 28             scmd.CommandText = "insert into _Stu values('" + sid + "','" + sname + "','" + ssex + "','" + sclass + "')";
 29 
 30             scmd.ExecuteNonQuery();
 31             Console.WriteLine("OK!");
 32 
 33             scon.Close();
 34 
 35 
 36         }
 37 
 38         public static void updateBysid()
 39         {
 40             Console.WriteLine("**************************修改记录***************************");
 41             Console.Write("学号：");
 42             string id = Console.ReadLine();
 43             Console.Write("姓名：");
 44             string name = Console.ReadLine();
 45             Console.Write("性别：");
 46             string sex = Console.ReadLine();
 47             Console.Write("班级：");
 48             string iclass = Console.ReadLine();
 49 
 50             SqlConnection scon = new SqlConnection("server=.;database=xx;uid=sa;pwd=111111");
 51             scon.Open();
 52             SqlCommand scmd = new SqlCommand();
 53             scmd.Connection = scon;
 54             scmd.CommandText = "update _Stu set sname='"+name
 55                 +"',ssex='"+sex+"',sclass='"+iclass+"' where     sid='"+id+"'";
 56 
 57             scmd.ExecuteNonQuery();
 58             Console.WriteLine("OK!");
 59             scon.Close();
 60 
 61 
 62         }
 63         public static void Read()
 64         {
 65             Console.WriteLine("**************************读取所有记录***************************");
 66             SqlConnection rcon = new SqlConnection("server=.;database=xx;uid=sa;pwd=111111");
 67             rcon.Open();
 68             SqlCommand rcmd = rcon.CreateCommand();
 69             rcmd.CommandText = "select * from _Stu";
 70             SqlDataReader re = rcmd.ExecuteReader();
 71             while (re.Read())
 72             {
 73                 Console.Write(re[0].ToString()+"	"+re[1].ToString()+"	"+re[2].ToString()+"	"+re[3].ToString()+"
");
 74             }
 75 
 76             rcon.Close();
 77 
 78         }
 79         public static void Cha()
 80         {
 81             Console.WriteLine("**************************查询记录***************************");
 82             Console.WriteLine("请输入查询条件：0：按学号 1：按姓名 2：按班级 3：按性别 ");
 83             string xz = Console.ReadLine();
 84             string tj = "";
 85             SqlConnection rcon = new SqlConnection("server=.;database=xx;uid=sa;pwd=111111");
 86             rcon.Open();
 87             SqlCommand rcmd = rcon.CreateCommand();
 88 
 89             switch (xz)
 90             {
 91                 case "0":
 92                     Console.Write("请输入需要查询的学号：");
 93                     tj = Console.ReadLine();
 94                     rcmd.CommandText = "select * from _Stu where sid='"+tj+"'";
 95                     break;
 96                 case "1":
 97                     Console.Write("请输入需要查询的姓名：");
 98                     tj = Console.ReadLine();
 99                     rcmd.CommandText = "select * from _Stu where sname='" + tj + "'";
100                     break;
101                 case "2":
102                     Console.Write("请输入需要查询的班级：");
103                     tj = Console.ReadLine();
104                     rcmd.CommandText = "select * from _Stu where sclass='" + tj + "'";
105                     break;
106                 case "3":
107                     Console.Write("请输入需要查询的性别：");
108                     tj = Console.ReadLine();
109                     rcmd.CommandText = "select * from _Stu where ssex='" + tj + "'";
110                     break;
111                 case "4":
112                     hh();
113                     break;
114                 default:
115                     Console.Write("别闹！");
116 
117                     break;
118             }
119             
120             SqlDataReader re = rcmd.ExecuteReader();
121             Console.WriteLine("**************************查询结果***************************");
122             while (re.Read())
123             {
124                 Console.Write(re[0].ToString() + "	" + re[1].ToString() + "	" + re[2].ToString() + "	" + re[3].ToString() + "
");
125             }
126 
127             rcon.Close();
128 
129         }
130         public static void hh()
131         { 
132         
133         }
134         public static void deleteBysid()
135         {
136             Console.WriteLine("**************************删除记录***************************");
137             Console.Write("请选择：0：学号 1：姓名 2：班级 3：性别");
138             string xz = Console.ReadLine();
139             SqlConnection scon=new SqlConnection("server=.;database=xx;uid=sa;pwd=111111");
140             scon.Open();
141             SqlCommand scmd=new SqlCommand();
142             scmd.Connection=scon;
143             string code="  ";
144             switch (xz)
145             {
146                 case "0":
147                     Console.Write("学号：");
148             string id = Console.ReadLine();
149             code = "delete from _Stu  where sid='" + id + "'";
150                     break;
151                 case "1":
152                     Console.Write("姓名：");
153                     string name = Console.ReadLine();
154                     code = "delete from _Stu  where sname='" + name + "'";
155 
156                     break;
157 
158                 case "2":
159                     Console.Write("班级：");
160                     string iclass = Console.ReadLine();
161                     code = "delete from _Stu  where scalss='" + iclass + "'";
162 
163                     break;
164 
165                 case "3":
166                     Console.Write("性别：");
167                     string sex = Console.ReadLine();
168                     code = "delete from _Stu  where ssex='" + sex+ "'";
169                     break;
170 
171                 default:
172                     Console.WriteLine("有错误!");
173                     break;
174             }
175             scmd.CommandText = code;
176             scmd.ExecuteNonQuery();
177             Console.WriteLine("OK!");
178             scon.Close();
179             
180 
181             
182         }
183 
184     }
185 }
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原文地址：https://www.cnblogs.com/lovesy2413/p/4475974.html