This example demonstrates a SELECT statement with a group of numeric columns, being converted into a null terminated string. It is a useful technique when there is a need to read and write number, which are larger than 16 digits. Also, this example demonstrates the overriding of datetime columns.
#include <iostream>
using namespace std;
#include <stdio.h>
#define OTL_ODBC_UNIX // Compile OTL 4.0/ODBC
#include <otlv4.h> // include the OTL 4.0 header file
otl_connect db; // connect object
void insert()
// insert rows into table
{
otl_stream o(50, // buffer size
"insert into test_tab values(:f1<double>,:f11<int>,:f2<char[31]>, GETDATE())",
// SQL statement
db // connect object
);
char tmp[32];
for(int i=1;i<=100;++i){
sprintf(tmp,"Name%d",i);
o<<(double)i<<i<<tmp;
}
}
void select()
{
otl_stream i;
i.set_all_column_types(otl_all_num2str | otl_all_date2str);
// map all numeric columns to strings as well as
// map all date columns to strings
i.open(50, // buffer size
"select * from test_tab "
"where f1>=:f11<int> "
" and f1<=:f12<int>*2",
// SELECT statement
db // connect object
);
// create select stream
char f1[40];
char f11[40];
char f2[31];
char f3[40];
i<<8<<8;
// SELECT automatically executes when all input variables are
// assigned. First portion of output rows is fetched to the buffer
while(!i.eof()){ // while not end-of-data
i>>f1>>f11>>f2>>f3;
cout<<"f1="<<f1<<", f11="<<f11<<", f2="<<f2<<", f3="<<f3<<endl;
}
i<<4<<4;
// SELECT automatically executes when all input variables are
// assigned. First portion of output rows is fetched to the buffer
while(!i.eof()){ // while not end-of-data
i>>f1>>f11>>f2>>f3;
cout<<"f1="<<f1<<", f11="<<f11<<", f2="<<f2<<", f3="<<f3<<endl;
}
}
int main()
{
otl_connect::otl_initialize(); // initialize ODBC environment
try{
db.rlogon("scott/tigger@freetds_sybsql"); // connect to ODBC
// It's recommended to use auto_commit_off() when OTL is used
// with FreeTDS/ODBC against Sybase in order to set the DB
// session's auto-commit to OFF. otl_connect::rlogon()'s auto-commit
// parameter has not effect. auto_commit_off() is a workaround, until
// a fix becomes available.
db.auto_commit_off();
otl_cursor::direct_exec
(
db,
"drop table test_tab",
otl_exception::disabled // disable OTL exceptions
); // drop table
otl_cursor::direct_exec
(
db,
"create table test_tab(f1 numeric, f11 int, f2 varchar(30), f3 datetime)"
); // create table
insert(); // insert records into table
select(); // select records from table
}
catch(otl_exception& 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;
}
f1=8, f11=8, f2=Name8, f3=2008-04-22 18:43:16.333
f1=9, f11=9, f2=Name9, f3=2008-04-22 18:43:16.333
f1=10, f11=10, f2=Name10, f3=2008-04-22 18:43:16.337
f1=11, f11=11, f2=Name11, f3=2008-04-22 18:43:16.337
f1=12, f11=12, f2=Name12, f3=2008-04-22 18:43:16.337
f1=13, f11=13, f2=Name13, f3=2008-04-22 18:43:16.337
f1=14, f11=14, f2=Name14, f3=2008-04-22 18:43:16.337
f1=15, f11=15, f2=Name15, f3=2008-04-22 18:43:16.337
f1=16, f11=16, f2=Name16, f3=2008-04-22 18:43:16.337
f1=4, f11=4, f2=Name4, f3=2008-04-22 18:43:16.333
f1=5, f11=5, f2=Name5, f3=2008-04-22 18:43:16.333
f1=6, f11=6, f2=Name6, f3=2008-04-22 18:43:16.333
f1=7, f11=7, f2=Name7, f3=2008-04-22 18:43:16.333
f1=8, f11=8, f2=Name8, f3=2008-04-22 18:43:16.333
Copyright © 1996-2024, Sergei Kuchin, email: skuchin@gmail.com, skuchin@gmail.com.
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