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<title>Example 607 (otl_stream::clean(), cleaning the SELECT stream's
error flags)</title>
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<h1>OTL 4.0, Example 607 (otl_stream::clean(), cleaning the SELECT
stream's
error flags)</h1>
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This example demonstrates the extended functionality of the <a
href="otl3_stream_class.htm#clean">otl_stream::clean()</a>
function.
<h2>Source Code</h2>
<pre>#include <iostream><br>#include <stdio.h><br>using namespace std;<br><br>#define <a
href="otl3_compile.htm#OTL_ODBC_ENTERPRISEDB">OTL_ODBC_ENTERPRISEDB</a> // Compile OTL 4.0/EnterpriseDB-ODBC<br>// Uncomment the #define below when used in Linux / Unix<br>//#define OTL_ODBC_UNIX<br><pre>#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(50, // 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>void select()<br>{ <br> <a
href="otl3_stream_class.htm">otl_stream</a> i(50, // buffer size<br> "select * from test_tab where f1>=:f11<char[40]> and f1<=:f12<char[40]>*2",<br> // SELECT statement<br> db // connect object<br> ); <br> // create select stream<br> <br> float f1;<br> char f2[31];<br> <br> try{<br> cout<<"====> Starting a fetch sequence...."<<endl;<br> i<<"xxx8"<<"xxx8"; // assigning :f11 = "xxx8", :f12 = "xxx8". It's obviously <br> // invalid for a numeric column<br> // SELECT automatically executes when all input variables are<br> // assigned. First portion of output rows is fetched to the buffer<br><br> while(!i.eof()){ // while not end-of-data<br> i>>f1>>f2;<br> cout<<"f1="<<f1<<", f2="<<f2<<endl;<br> } <br> }catch(otl_exception& p){<br> cerr<<"===> A database exception is caught: "<<endl;<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> cerr<<"===> Cleaning up the stream's error flags"<<endl;<br> i.<a
href="otl3_stream_class.htm#clean">clean()</a>;<br> }<br><br> cout<<"====> Starting another fetch sequence..."<<endl;<br> i<<"4"<<"4"; // assigning :f11 = :"4, :f12 = "4"<br> // SELECT automatically executes when all input variables are<br> // assigned. First portion of output rows is fetched to the buffer<br><br> while(!i.eof()){ // while not end-of-data<br> i>>f1>>f2;<br> cout<<"f1="<<f1<<", f2="<<f2<<endl;<br> }<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@edbsql"); // 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> insert(); // insert records into table<br> select(); // select records from table<br><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>}<br><br></pre></pre>
<h2>Output</h2>
<pre><pre>====> Starting a fetch sequence....<br>===> A database exception is caught:<br>ERROR: invalid input syntax for integer: "xxx8";<br>Error while executing the query<br>select * from test_tab where f1>=? and f1<=? *2<br><br>===> Cleaning up the stream's error flags<br>====> Starting another fetch sequence...<br>f1=4, f2=Name4<br>f1=5, f2=Name5<br>f1=6, f2=Name6<br>f1=7, f2=Name7<br>f1=8, f2=Name8<br><hr
width="100%"></pre>
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