OTL 4.0, Example 118 (otl_stream::set_flush(), DB2-CLI)

Example 118 (otl_stream::set_flush(), DB2-CLI)

This example demonstrates the otl_stream::set_flush() function.

Source Code

#include <iostream>
using namespace std;

#include <stdio.h>

#define OTL_DB2_CLI // Compile OTL 4.0/DB2_CLI
#include <otlv4.h> // include the OTL 4.0 header file

otl_connect db; // connect object

void insert1()
// insert rows into table
{ 
 otl_stream o; // define an otl_stream variable

 o.set_flush(false); // set the auto-flush flag to OFF.

o.open(200, // buffer size
       "insert into test_tab values(:f1<float>,:f2<char[31]>)", 
           // SQL statement
       db // connect object
      );
 char tmp[32];

 for(int i=1;i<=100;++i){
  sprintf(tmp,"Name%d",i);
  o<<(float)i<<tmp;
  if(i%55==0)
   throw "Throwing an exception";
 }
 o.flush(); // when the auto-flush flag is OFF, an explicit flush
            // of the stream buffer is required in case of successful
            // completion of execution of the INSERT statement.
// In case of a raised exception, the stream buffer would not be flushed.           
}

void insert2()
// insert rows into table
{ 
 otl_stream o; // define an otl_stream variable

 o.set_flush(false); // set the auto-flush flag to OFF.

o.open(200, // buffer size
       "insert into test_tab values(:f1<float>,:f2<char[31]>)", 
           // SQL statement
       db // connect object
      );
 char tmp[32];

 for(int i=1;i<=100;++i){
  sprintf(tmp,"Name%d",i);
  o<<(float)i<<tmp;
//  if(i%55==0)
//   throw "Throwing an exception";
 }
 o.flush(); // when the auto-flush flag is OFF, an explicit flush
            // of the stream buffer is required in case of successful
            // completion of execution of the INSERT statement.
// In case of a raised exception, the stream buffer would not be flushed.           
}

void select()
{ 
 otl_stream i(50, // buffer size
              "select * from test_tab where f1>=:f<int> and f1<=:ff<int>*2",
                 // SELECT statement
              db // connect object
             ); 
   // create select stream
 
 float f1;
 char f2[31];

 i<<8<<8; // assigning :f = 8, :ff = 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 :f = 4, :ff = 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

  try{
   insert1(); // insert records into table
  }catch(const char* p){
   cout<<p<<endl;
  }
  cout<<"Selecting the first time around:"<<endl;
  select(); // select records from table
  
  insert2();
  cout<<"Selecting the second time around:"<<endl;
  select();

 }

 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

Throwing an exception
Selecting the first time around:
Selecting the second time around:
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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