OTL 4.0, Example 635 (Datatype override in SELECT)

This example demonstrates a SELECT statement with a numeric column, being converted into a null terminated string. It is a useful technique when there is a need to read and write numbers, which are larger than 16 digits.

Source Code

#include <iostream>
using namespace std;

#include <stdio.h>
// Compile OTL 4.0/ODBC in Windows. Informix CLI uses the  
// regular ODBC header files in Windows
#define OTL_ODBC

// Uncomment the #defines below in Linux / Unix
//#define OTL_ODBC_UNIX
//#define OTL_INFORMIX_CLI
#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+:f1<int>,:f2<char[31]>)", 
                 // SQL statement
              db // connect object
             );
 char tmp[32];

 for(int i=1;i<=100;++i){
  sprintf(tmp,"Name%d",i);
  o<<i<<tmp;
 }
}

void select()

 otl_stream i;

 i.set_column_type(1,otl_var_char,40); // use a string(40) instead of default double
 i.open(50, // buffer size
        "select * from test_tab "
        "where f1>=12345678900000000+:f11<int> "
        "  and f1<=12345678900000000+:f12<int>*2",
           // SELECT statement
        db // connect object
       ); 
   // create select stream
 
 char f1[40];
 char f2[31];

 i<<8<<8; // assigning :f11 = 8, :f12 = 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>>f2;
  cout<<"f1="<<f1<<", f2="<<f2<<endl;
 }

 i<<4<<4; // assigning :f11 = 4, :f12 = 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>>f2;
  cout<<"f1="<<f1<<", f2="<<f2<<endl;
 }

}

int main()
{
 otl_connect::otl_initialize(); // initialize Infomix CLI environment
 try{

  db.rlogon("informix/tigger@informixsql"); // connect to Informix

  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 int8, f2 varchar(30))"
    );  // 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 Informix

 return 0;

}

Output

f1=12345678900000008, f2=Name8
f1=12345678900000009, f2=Name9
f1=12345678900000010, f2=Name10
f1=12345678900000011, f2=Name11
f1=12345678900000012, f2=Name12
f1=12345678900000013, f2=Name13
f1=12345678900000014, f2=Name14
f1=12345678900000015, f2=Name15
f1=12345678900000016, f2=Name16
f1=12345678900000004, f2=Name4
f1=12345678900000005, f2=Name5
f1=12345678900000006, f2=Name6
f1=12345678900000007, f2=Name7
f1=12345678900000008, f2=Name8

Examples ContentsGo Home

Copyrigh6 © 1996-2015, Sergei Kuchin, email: skuchin@gmail.com, skuchin@gmail.com/a>.

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.