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_MSSQL_2005 // Compile OTL 4/ODBC, MS SQL 2005
#define OTL_FREETDS_ODBC_WORKAROUNDS // Enable the FreeTDS / ODBC workarounds for MS SQL
//#define OTL_ODBC // Compile OTL 4/ODBC. Uncomment this when used with MS SQL 7.0/ 2000
//#define OTL_ODBC_UNIX // Compile OTL 4 / ODBC. Uncomment this when used in Linux / Unix
#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(12345678900000000+convert(numeric,:f1<int>),: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<<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>=12345678900000000+convert(numeric,:f11<int>) "
" and f1<=12345678900000000+convert(numeric,: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/tiger@freetds_mssql"); // connect to ODBC
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=12345678900000008, f11=8, f2=Name8, f3=2001-02-03 21:29:49.560
f1=12345678900000009, f11=9, f2=Name9, f3=2001-02-03 21:29:49.560
f1=12345678900000010, f11=10, f2=Name10, f3=2001-02-03 21:29:49.560
f1=12345678900000011, f11=11, f2=Name11, f3=2001-02-03 21:29:49.560
f1=12345678900000012, f11=12, f2=Name12, f3=2001-02-03 21:29:49.560
f1=12345678900000013, f11=13, f2=Name13, f3=2001-02-03 21:29:49.560
f1=12345678900000014, f11=14, f2=Name14, f3=2001-02-03 21:29:49.560
f1=12345678900000015, f11=15, f2=Name15, f3=2001-02-03 21:29:49.560
f1=12345678900000016, f11=16, f2=Name16, f3=2001-02-03 21:29:49.560
f1=12345678900000004, f11=4, f2=Name4, f3=2001-02-03 21:29:49.560
f1=12345678900000005, f11=5, f2=Name5, f3=2001-02-03 21:29:49.560
f1=12345678900000006, f11=6, f2=Name6, f3=2001-02-03 21:29:49.560
f1=12345678900000007, f11=7, f2=Name7, f3=2001-02-03 21:29:49.560
f1=12345678900000008, f11=8, f2=Name8, f3=2001-02-03 21:29:49.560
Copyright © 1996-2024, Sergei Kuchin, email: skuchin@gmail.com, skuchin@gmail.com.
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. THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.