📄 otl4_ex218.htm
字号:
<!DOCTYPE html PUBLIC "-//w3c//dtd html 4.0 transitional//en">
<html>
<head>
<meta http-equiv="Content-Type"
content="text/html; charset=iso-8859-1">
<meta name="Author" content="Sergei Kuchin">
<meta name="GENERATOR"
content="Mozilla/4.77 [en] (Win95; U) [Netscape]">
<meta name="KeyWords"
content="OTL, Oracle, ODBC, DB2, CLI, database API, C++, Template Library">
<title>OTL 4.0, Example 217 (otl_stream::cancel() and DB2-CLi)</title>
</head>
<body>
<center>
<h1>OTL 4.0, Example 218 (otl_stream::cancel() and ODBC)</h1>
</center>
<h1>
Example 218 (otl_stream::cancel() and ODBC)</h1>
This example demonstrates how to use <a
href="otl3_stream_class.htm#cancel">otl_stream::cancel()</a>
in OTL/ODBC, OTL/DB2-CLI. The example works in Windows, VC++, only.
With
small modifications, the example can be ported to Unix, pthreads.
<h2>Source Code</h2>
<pre>#include <iostream><br>using namespace std;<br><br>#include <stdio.h><br>#include <windows.h><br>#include <process.h></pre>
<pre>#define OTL_ODBC // Compile OTL 4.0/ODBC<br>#include <otlv4.h> // include the OTL 4.0 header file<br><br><a
href="otl3_connect_class.htm">otl_connect</a> db; // connect object<br><br>void insert()<br>// insert rows into table<br>{ <br> <a
href="otl3_stream_class.htm">otl_stream</a> o(1, // buffer size<br> "insert into test_tab values(:f1<float>,:f2<char[31]>)", <br> // SQL statement<br> db // connect object<br> );<br> char tmp[32];<br><br> for(int i=1;i<=100;++i){<br> sprintf(tmp,"Name%d",i);<br> o<<(float)i<<tmp;<br> }<br>}<br><br><a
href="otl3_stream_class.htm">otl_stream</a> s;<br><br>void select(void* dummy_par)<br>{ <br> try{<br><br> cout<<"Selecting..."<<endl;<br><br> s.open(1, // buffer size<br> "select count(*) "<br> "from test_tab a1, test_tab a2, test_tab a3, "<br> " test_tab a4, test_tab a5 "<br> "where 1=:f1<int>",<br> // SELECT statement<br> db // connect object<br> ); <br> // Create select stream.<br> // The ":f1" dummy input parameter is needed to give the stream<br> // a chance to initialize its internal variables with the SELECT statement<br> // BEFORE the SELECT statement starts executing<br> <br> int count;<br><br> s<<1; // Now, forcing the execution of the SQL<br><br> while(!s.eof()){ // while not end-of-data<br> s>>count;<br> cout<<"count="<<count<<endl;<br> }<br> }catch(otl_exception& p){<br> cerr<<"Select() ===> "<<p.msg<<endl; // print out error message<br> cerr<<"Select() ===> "<<p.stm_text<<endl; // print out SQL that caused the error<br> cerr<<"Select() ===> "<<p.var_info<<endl; // print out the vari }<br> }<br> _endthread();<br>}<br><br>void cancel(void* dummy_par)<br>{ <br> try{<br> cout<<"Cancelling the SQL"<<endl;<br> s.<a
href="otl3_stream_class.htm#cancel">cancel</a>();<br> }catch(otl_exception& p){<br> cout<<"Cancel() ===> "<<p.msg<<endl; // print out error message<br> cout<<"Cancel() ===> "<<p.stm_text<<endl; // print out SQL that caused the error<br> cout<<"Cancel() ===> "<<p.var_info<<endl; // print out the vari }<br> }<br> cout<<"End of Cancelling"<<endl;<br> _endthread();<br><br>}<br><br>int main()<br>{<br> <a
href="otl3_connect_class.htm">otl_connect::otl_initialize</a>(); // initialize the environment<br> try{<br><br> db.rlogon("scott/tiger@postgresql"); // connect to the database<br><br> <a
href="otl3_const_sql.htm">otl_cursor::direct_exec<br></a> (<br> db,<br> "drop table test_tab",<br> otl_exception::disabled // disable OTL exceptions<br> ); // drop table<br><br> <a
href="otl3_const_sql.htm">otl_cursor::direct_exec<br></a> (<br> db,<br> "create table test_tab(f1 int, f2 varchar(30))"<br> ); // create table<br><br> db.commit();<br><br> insert(); // insert records into table<br> _beginthread(select,0,NULL);<br> Sleep(2000);<br> _beginthread(cancel,0,NULL);<br> Sleep(10000);<br> cout<<"End of program"<<endl;<br> }<br><br> catch(<a
href="otl3_exception_class.htm">otl_exception</a>& p){ // intercept OTL exceptions<br> cerr<<p.msg<<endl; // print out error message<br> cerr<<p.stm_text<<endl; // print out SQL that caused the error<br> cerr<<p.var_info<<endl; // print out the variable that caused the error<br> }<br><br> db.logoff(); // disconnect from the database<br><br> return 0;<br><br>}</pre>
<h2>
Output</h2>
<pre>Selecting...<br>Cancelling the SQL<br>End of Cancelling<br>Select() ===> ERROR: Query was cancelled.<br>;<br>ERROR: Query was cancelled.<br><br>Select() ===> select count(*) from test_tab a1, test_tab a2, test_tab a3, t<br>est_tab a4, test_tab a5 where 1=?<br>Select() ===><br>End of program<br><br><br><hr
width="100%"></pre>
<center><a href="otl3_examples.htm">Examples</a> <a href="otl3.htm">Contents</a><a
href="home.htm">Go
Home</a></center>
<p>Copyright © 1996, 2008, Sergei Kuchin, email: <a
href="mailto:skuchin@aceweb.com">skuchin@aceweb.com</a>,
<a href="mailto:skuchin@gmail.com">skuchin@gmail.com
<script language="JavaScript">
<!-- hide from old browsers
var modDate = new Date(document.lastModified)
document.write("<i> Last Updated:</i> " + (modDate.getMonth()+1) + "/" +
modDate.getDate() + "/" + "0"+(modDate.getYear())%100+".");
//-->
</script></a>.
</p>
<p><i>Permission to use, copy, modify and redistribute this document
for
any purpose is hereby granted without fee, provided that the above
copyright
notice appear in all copies.</i>
</p>
<script type="text/javascript">
var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www.");
document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E"));
</script>
<script type="text/javascript">
var pageTracker = _gat._getTracker("UA-5456201-1");
pageTracker._trackPageview();
</script>
</body>
</html>
⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -