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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"><HTML><HEAD> <TITLE>OTL 4.0, Example 32 (otl_stream::describe_select() with a simple Select)</TITLE> <META NAME="Author" CONTENT="Sergei Kuchin"> <META NAME="GENERATOR" CONTENT="Mozilla/3.03Gold (Win95; I) [Netscape]"> <META NAME="KeyWords" CONTENT="OTL, Oracle, ODBC, DB2, CLI, database API, C++, Template Library"></HEAD><BODY><H1 ALIGN=CENTER>OTL 4.0, Example 32<BR>(otl_stream::describe_select() with a simple Select)</H1><H1><A NAME="example1"></A>Example 32 (otl_stream::describe_select() witha simple Select)</H1><P>This example demonstrates the <A HREF="otl3_stream_class.htm#describe_select">otl_stream::describe_select</A>()with a simple SELECT statement.</P><H2>Source Code</H2><PRE>#include <iostream>using namespace std;#include <stdio.h></PRE><PRE>#define OTL_ODBC // Compile OTL 4.0/ODBC#include <otlv4.h> // include the OTL 4.0 header file<A HREF="otl3_connect_class.htm">otl_connect</A> db; // connect objectvoid select(){ <A HREF="otl3_stream_class.htm">otl_stream</A> i(1, // buffer size "select * from test_tab where f1>=:f<int> and f1<=:f*2", // SELECT statement db // connect object ); // create select stream <A HREF="otl3_stream_class.htm#otl_column_desc">otl_column_desc</A>* desc; int desc_len; desc=i.<A HREF="otl3_stream_class.htm#describe_select">describe_select</A>(desc_len); for(int n=0;n<desc_len;++n){ cout<<"========== COLUMN #"<<n+1<<" ==========="<<endl; cout<<"name="<<desc[n].name<<endl; cout<<"dbtype="<<desc[n].dbtype<<endl; cout<<"<A HREF="otl3_stream_class.htm#otl_var_dbtype">otl_var_dbtype</A>="<<desc[n].otl_var_dbtype<<endl; cout<<"dbsize="<<desc[n].dbsize<<endl; cout<<"scale="<<desc[n].scale<<endl; cout<<"prec="<<desc[n].prec<<endl; cout<<"nullok="<<desc[n].nullok<<endl; } }int main(){ <A HREF="otl3_connect_class.htm">otl_connect::otl_initialize</A>(); // initialize ODBC environment try{ db.rlogon("uid=scott;pwd=tiger;dsn=mssql"); // connect to ODBC <A HREF="otl3_const_sql.htm">otl_cursor::direct_exec</A> ( db, "drop table test_tab", otl_exception::disabled // disable OTL exceptions ); // drop table <A HREF="otl3_const_sql.htm">otl_cursor::direct_exec</A> ( db, "create table test_tab(f1 int, f2 varchar(30), f3 text)" ); // create table select(); // select records from table } catch(<A HREF="otl3_exception_class.htm">otl_exception</A>& p){ // intercept OTL exceptions cerr<<p.msg<<endl; // print out error message cerr<<p.stm_text<<endl; // print out SQL that caused the error cerr<<p.var_info<<endl; // print out the variable that caused the error } db.logoff(); // disconnect from ODBC return 0;}</PRE><H2>Output</H2><PRE>========== COLUMN #1 ===========name=f1dbtype=4otl_var_dbtype=2dbsize=10scale=0prec=10nullok=1========== COLUMN #2 ===========name=f2dbtype=12otl_var_dbtype=1dbsize=30scale=0prec=30nullok=1========== COLUMN #3 ===========name=f3dbtype=-1otl_var_dbtype=9dbsize=2147483647scale=0prec=2147483647nullok=1<HR WIDTH="100%"></PRE><CENTER><P><A HREF="otl3_examples.htm">Examples</A> <A HREF="otl3.htm">Contents</A><A HREF="home.htm">Go Home</A> </P></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@yahogmail</A><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>.</P><P><I>Permission to use, copy, modify and redistribute this document forany purpose is hereby granted without fee, provided that the above copyrightnotice 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
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