OTL 4.0, Example 264 (OTL stream read iterator, simple SELECT, DB2 CLI)

Example 264 (OTL stream read iterator, simple SELECT, DB2 CLI)

This example demonstrates otl_stream_read_iterator for DB2 CLI.

Source Code

#include <iostream>
using namespace std;

#include <stdio.h>

#define OTL_DB2_CLI// Compile OTL 4.0/DB2-CLI
#define OTL_STREAM_READ_ITERATOR_ON
#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<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(50, // buffer size
              "select * from test_tab "
   	      "where f1>=:f11<int> and f1<=:f12<int>*2",
                 // SELECT statement
              db // connect object
             ); 
   // create select stream
 
 int f1;
 char f2[31];
 otl_stream_read_iterator<otl_stream,otl_exception,otl_lob_stream> rs;

 rs.attach(i); // attach the iterator "rs" to the stream "i".
 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


#if (defined(_MSC_VER) && _MSC_VER>=1600) || defined(OTL_CPP_11_ON)
// C++11 (or higher) compiler
 for(auto& it : rs){
  it.get(1,f1);
  it.get(2,f2);
  cout<<"f1="<<f1<<", f2="<<f2<<endl;
 }
#else
// C++98/03 compiler
 while(rs.next_row()){ // while not end-of-data
  rs.get(1,f1);
  rs.get(2,f2);
  cout<<"f1="<<f1<<", f2="<<f2<<endl;
 }
#endif


 rs.detach(); // detach the itertor from the stream

 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 DB2 CLI environment
 try{

  db.rlogon("scott/tiger@db2sql"); // connect to DB2 CLI

  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 int, 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 DB2 CLI

 return 0;

}

Output

f1=8, f2=Name8
f1=9, f2=Name9
f1=10, f2=Name10
f1=11, f2=Name11
f1=12, f2=Name12
f1=13, f2=Name13
f1=14, f2=Name14
f1=15, f2=Name15
f1=16, f2=Name16
f1=4, f2=Name4
f1=5, f2=Name5
f1=6, f2=Name6
f1=7, f2=Name7
f1=8, f2=Name8

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