1 USING SYSTEM;
 2 USING SYSTEM.COLLECTIONS.GENERIC;
 3 USING SYSTEM.DATA;
 4 USING SYSTEM.DATA.SQLCLIENT;
 5  
 6 CLASS PROGRAM
 7 {
 8     STATIC VOID MAIN()
 9     {
10         STRING CONNECTIONSTRING = GETCONNECTIONSTRING();
11         STRING QUERYSTRING = "SELECT CATEGORYID, CATEGORYNAME FROM DBO.CATEGORIES;";
12         USING (SQLCONNECTION CONNECTION = NEW SQLCONNECTION(CONNECTIONSTRING))
13         {
14             SQLCOMMAND COMMAND = CONNECTION.CREATECOMMAND();
15             COMMAND.COMMANDTEXT = QUERYSTRING;
16             TRY
17             {
18                 CONNECTION.OPEN();
19                 SQLDATAREADER READER = COMMAND.EXECUTEREADER();
20                 WHILE (READER.READ())
21                 {
22                     CONSOLE.WRITELINE("\T{0}\T{1}",READER[0], READER[1]);
23                 }
24 CONSOLE.READKEY();
25                 READER.CLOSE();
26             }
27             CATCH (EXCEPTION EX)
28             {
29                 CONSOLE.WRITELINE(EX.MESSAGE);
30             }
31         }
32     }
33  
34     STATIC PRIVATE STRING GETCONNECTIONSTRING()
35     {
36         // TO AVOID STORING THE CONNECTION STRING IN YOUR CODE,
37         // YOU CAN RETRIEVE IT FROM A CONFIGURATION FILE.
38         RETURN "DATA SOURCE=(LOCAL);INITIAL CATALOG=NORTHWIND;"+ "INTEGRATED SECURITY=SSPI";
39     }
40 }

1 private static void OpenSqlConnection(string connectionString)
2 {
3         using (SqlConnection connection = new SqlConnection(connectionString))
4         {
5             connection.Open();
6             Console.WriteLine("ServerVersion: {0}", connection.ServerVersion);
7             Console.WriteLine("State: {0}", connection.State);
8         }
9 }

 1 //参数  执行的sql 语句  ，连接字符串
 2 private static void CreateCommand(string queryString,string connectionString)
 3 {
 4         using (SqlConnection connection = new SqlConnection(connectionString))
 5         {
 6             SqlCommand command = new SqlCommand();
 7              
 8             command.Connection = connection;
 9 
10             command.CommandTimeout = 15;
11             command.CommandType = CommandType.Text;
12             command.CommandText = queryString;
13             connection.Open();
14 //查询
15             SqlDataReader reader = command.ExecuteReader();
16             while (reader.Read())
17             {
18                 Console.WriteLine(String.Format("{0}, {1}",reader[0], reader[1]));
19             }
20         }
21 }

 1 static void Main(string[] args)    
 2          {    
 3    
 4              SqlConnection sqlConn = new SqlConnection(    
 5                  ConfigurationManager.ConnectionStrings["ConnStr"].ConnectionString);    
 6              SqlTransaction sqlTrans = null;    
 7             try   
 8              {    
 9                  sqlConn.Open();    
10                  sqlTrans = sqlConn.BeginTransaction();//事务开始    
11                  SqlCommand sqlComm = new SqlCommand("", sqlConn, sqlTrans);    
12                  sqlComm.CommandTimeout = 120;    
13                  sqlComm.CommandType = System.Data.CommandType.Text;    
14    
15                 string insertSql = "insert into dbo.TransTestTable values (66,'66');";    
16                 string updateSql = "update dbo.TransTestTable set [Name] = '77' where [Id] = 66;";    
17    
18                  sqlComm.CommandText = insertSql;    
19                  sqlComm.ExecuteNonQuery();//执行insert    
20    
21                  sqlComm.CommandText = updateSql;    
22                  sqlComm.ExecuteNonQuery();//执行update    
23                 //throw new Exception("test exception.the transaction must rollback");    
24    
25                  sqlTrans.Commit();//事务提交    
26              }    
27             catch (Exception ex)    
28              {    
29                  sqlTrans.Rollback();//事务回滚    
30                  Console.WriteLine(ex.Message);    
31              }    
32             finally   
33              {    
34                 if (sqlConn.State != System.Data.ConnectionState.Closed)    
35                      sqlConn.Close();    
36              }    
37    
38              Console.ReadLine();    
39          }  

https://www.cnblogs.com/ldy_ai/p/3644619.html

private void button1_Click(object sender, EventArgs e)
        {
            SqlConnection conn = new SqlConnection();
            conn.ConnectionString = "Data Source=(local);Initial Catalog=school;User ID=sa";
            conn.Open();
            //注意此处为一个事务开始之处
            SqlTransaction sqltran = conn.BeginTransaction();
            string sqlstring = "insert into student(sno,sname) values(3390220,'张三')";
            SqlCommand comm = new SqlCommand(sqlstring, conn);
            comm.Transaction = sqltran;
            int p = comm.ExecuteNonQuery();
            sqltran.Commit();
            //此处为一个事务正常结束之处
            comm.Dispose();
            comm.Clone();
            conn.Dispose();
            conn.Close();
        }
/*
第一步：通过连接对象产生事务对象sqltran；
第二步：将事务对象sqltran绑定到命令对象的Transaction属性；
 第三步：执行命令对象；
第四步：通过事务对象sqltran的Commit（）方法，提交事务，或者通过事务对象sqltran的Rollback（）方法回滚事务。


*/