How to connect Oracle with C #

Try to connect to Oracle and use the oraclecommand to read records in the database, which is displayed on the console: 1 using system;
2 using system. Data;
3 using system. Data. oracleclient;
4
5. Public class mainclass
6 {
7 static void main ()
8 {
9 oracleconnection conn = new oracleconnection ();
10 conn. statechange + = new statechangeeventhandler (onstatechanged );
11 conn. connectionstring = "Data Source = chenchong; user id = system; Password = ;";
12 try
13 {
14 conn. open ();
15 console. writeline ("the database connection is successfully opened. ");
16 oraclecommand command = new oraclecommand ();
17 // command. commandtext = "";
18 command. commandtext = "select nsmc from Scott. NSR where nsmc like: pnsrmc order by nsmc ";
19 command. Connection = conn;
20 oracleparameter parameter = command. Parameters. Add ("pnsrmc", oracletype. varchar );
21 parameter. value = "_ country % ";
22 oracledatareader reader = command. executereader ();
23
24 // verify whether two datareader s can be opened simultaneously
25 oraclecommand command2 = new oraclecommand ();
26 command2.commandtext = "select count (*) from Scott. NSR ";
27 command2.connection = conn;
28 oracledatareader reader2 = command2.executereader ();
29 reader2.read ();
30 console. writeline ("the database has a total of {0} records. ", Reader2.getint32 (0 ));
31 reader2.close ();
32
33 while (reader. Read ())
34 {
35 if (! Reader. isdbnull (reader. getordinal ("nsmc ")))
36 {
37 console. writeline (reader. getstring (reader. getordinal ("nsmc"). Trim ());
38}
39 // string S = NULL;
40 // console. writeline (s );
41}
42 command. commandtext = "select count (nsmc) from Scott. NSR where nsmc like: pnsrmc order by nsmc ";
43 console. writeline ("A total of {0} records meet the condition. ", Command. executescalar ());
44}
45 catch (exception E)
46 {
47 console. writeline ("exception: {0}", E. tostring ());
48}
49 finally
50 {
51 if (Conn! = NULL)
52 {
53 conn. Close ();
54}
55}
56
57 console. Readline ();
58}
59
60 Private Static void onstatechanged (Object sender, statechangeeventargs E)
61 {
62 console. writeline ("the database connection status has changed. The original status is {0} and the current status is {1 }. ", E. originalstate, E. currentstate );
63}
64}