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📄 otl4_ex326.htm

📁 otl是c++数据库封装好的一个数据库接口
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  <title>OTL 4.0, Example 326 (otl_long_string container and a LONG
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<h1>OTL 4.0, Example 326 (otl_long_string container and a LONG BYTE
column)</h1>
</center>
<h1>
Example 326 (otl_long_string container and a LONG VARCHAR column)</h1>
This example demonstrates simple INSERT/SELECT with otl_long_string
container
and a LONG BYTE column.
<h2>Source Code</h2>
<pre>#include &lt;iostream&gt;<br>using namespace std;<br><br>#include &lt;stdio.h&gt;</pre>
<pre>#define <a href="otl3_compile.htm#OTL_ODBC">OTL_ODBC</a> // Compile OTL 4.0/ODBC<br>// #define OTL_ODBC_UNIX // uncomment this line if UnixODBC is used<br>#include &lt;otlv4.h&gt; // 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(void)<br>// insert rows into table<br>{&nbsp;<br><br>&nbsp;<a
 href="otl3_long_string.htm">otl_long_string</a> f2(7000); // define long string variable<br>&nbsp;db.<a
 href="otl3_connect_class.htm#set_max_long_size">set_max_long_size</a>(7000); // set maximum long string size for connect object<br><br>&nbsp;<a
 href="otl3_stream_class.htm">otl_stream</a> o(1, // buffer size needs to be set to 1<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; "insert into test_tab values(:f1&lt;int&gt;,:f2&lt;<a
 href="otl3_bind_variables.htm#varchar_long">varchar_long</a>&gt;)",&nbsp;<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; // INSERT statement<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; db // connect object<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; );<br><br><br>&nbsp;for(int i=1;i&lt;=10;++i){<br>&nbsp; for(int j=0;j&lt;5000;++j)<br>&nbsp;&nbsp; f2[j]='*';<br>&nbsp; f2[5000]='?';<br>&nbsp; f2.<a
 href="otl3_long_string.htm#set_len">set_len</a>(5001);<br>&nbsp; o&lt;&lt;i&lt;&lt;f2;<br>&nbsp;}<br>}<br><br>void select(void)<br>{&nbsp;<br>&nbsp;otl_long_string f2(7000); // define long string variable<br>&nbsp;db.set_max_long_size(7000); // set maximum long string size for connect object<br><br>&nbsp;otl_stream i(1, // buffer size needs to be set to 1 in case of TEXT columns<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; "select * from test_tab",<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; // SELECT statement<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; db // connect object<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; );&nbsp;<br>&nbsp;&nbsp; // create select stream<br>&nbsp;<br>&nbsp;int f1;<br><br><br>&nbsp;while(!i.eof()){ // while not end-of-data<br>&nbsp; i&gt;&gt;f1&gt;&gt;f2;<br>&nbsp; cout&lt;&lt;"f1="&lt;&lt;f1&lt;&lt;", f2="&lt;&lt;f2[0]&lt;&lt;f2[f2.len()-1]&lt;&lt;", len="&lt;&lt;f2.len()&lt;&lt;endl;<br>&nbsp;}<br><br>}</pre>
<pre>int main()<br>{<br>&nbsp;<a href="otl3_connect_class.htm">otl_connect::otl_initialize</a>(); // initialize ODBC environment<br>&nbsp;try{<br><br>  db.rlogon("scott/tiger@sapdbsql");<br><br>&nbsp; <a
 href="otl3_const_sql.htm">otl_cursor::direct_exec<br></a>&nbsp;&nbsp; (<br>&nbsp;&nbsp;&nbsp; db,<br>&nbsp;&nbsp;&nbsp; "drop table test_tab",<br>&nbsp;&nbsp;&nbsp; otl_exception::disabled // disable OTL exceptions<br>&nbsp;&nbsp; ); // drop table<br><br>&nbsp; <a
 href="otl3_const_sql.htm">otl_cursor::direct_exec<br></a>&nbsp;&nbsp; (<br>&nbsp;&nbsp;&nbsp; db,<br>&nbsp;&nbsp;&nbsp; "create table test_tab(f1 int, f2 long varchar)"<br>&nbsp;&nbsp;&nbsp; );&nbsp; // create table<br><br>&nbsp; insert(); // insert records into table<br>&nbsp; select(); // select records from table<br><br>&nbsp;}<br><br>&nbsp;catch(<a
 href="otl3_exception_class.htm">otl_exception</a>&amp; p){ // intercept OTL exceptions<br>&nbsp; cerr&lt;&lt;p.msg&lt;&lt;endl; // print out error message<br>&nbsp; cerr&lt;&lt;p.stm_text&lt;&lt;endl; // print out SQL that caused the error<br>&nbsp; cerr&lt;&lt;p.sqlstate&lt;&lt;endl; // print out SQLSTATE message<br>&nbsp; cerr&lt;&lt;p.var_info&lt;&lt;endl; // print out the variable that caused the error<br>&nbsp;}<br><br>&nbsp;db.logoff(); // disconnect from ODBC<br><br>&nbsp;return 0;<br><br>}</pre>
<h2>
Output</h2>
<pre>f1=1, f2=*?, len=50001<br>f1=2, f2=*?, len=50001<br>f1=3, f2=*?, len=50001<br>f1=4, f2=*?, len=50001<br>f1=5, f2=*?, len=50001<br>f1=6, f2=*?, len=50001<br>f1=7, f2=*?, len=50001<br>f1=8, f2=*?, len=50001<br>f1=9, f2=*?, len=50001<br>f1=10, f2=*?, len=50001<br><br><hr
 width="100%"></pre>
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