OTL 4.0, Example 712 (END-OF-ROW check)

This example demonstrates how to use the "end-of-row" function / stream manipulators with SELECT and INSERT statements.

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 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<<endr; // OTL stream manipulator "endr" checks 
                   // the "end of row" condition. As time goes on,
                   // the table layout may change, and the end-of-row check
                   // may throw an exception if the end-of-row condition
                   // fails.
 }
 o.flush(); // flush the stream dirty buffer
 // example of a faied end-of-row condition
 try{
  o<<i;
  // input for bind variable :f2 is missing
  o<<endr; // this will throw an exception
 }catch(otl_exception& p){
  o.clean(1); // reset the stream state
  cerr<<"ERROR CODE="<<p.msg<<endl; // print out error message
  cerr<<"ERROR SQL STM="<<p.stm_text<<endl; // print out SQL that caused the error
  cerr<<"ERROR VAR INFO="<<p.var_info<<endl; // print out the variable that caused the error
 }
}

void select()
{ 
 otl_stream i(50, // buffer size
              "select * from test_tab where f1>=:f_1<int><int> and f1<=:f_2<int>*2",
                 // SELECT statement
              db // connect object
             ); 
   // create select stream
 
 int f1;
 char f2[31];

 i<<8; // assigning :f_1 = 8, :f_2 = 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>>endr; // endr checks the end-of-row condition. As times goes on,
                   // The output column list on the SELECT statement may change,
                   // and the endr check may an exception.
  cout<<"f1="<<f1<<", f2="<<f2<<endl;
 }

 i<<4; // assigning :f_1 = 4, :f_2 = 4 
   // SELECT automatically executes when all input variables are
   // assigned. First portion of output rows is fetched to the buffer
 try{
// example of a failed end-of-row check
   while(!i.eof()){ // while not end-of-data
    i>>f1;
    // reading of the f2 output column is missing
    i>>endr; // this will throw an exception
    cout<<"f1="<<f1<<", f2="<<f2<<endl;
   }
 }catch(otl_exception& p){
  cerr<<"ERROR CODE (SELECT) ="<<p.msg<<endl; // print out error message
  cerr<<"ERROR SQL STM (SELECT) ="<<p.stm_text<<endl; // print out SQL that caused the error
  cerr<<"ERROR VAR INFO (SELECT) ="<<p.var_info<<endl; // print out the variable that caused the error
 }

}

int main()
{
 otl_connect::otl_initialize(); // initialize the database API
 try{

  db.rlogon("scott/tiger@db2sql"); // connect to the database

  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 the database

 return 0;

}

Output

ERROR CODE=END-OF-ROW check failed
ERROR SQL STM=insert into test_tab values(:f1     ,:f2          )
ERROR VAR INFO=
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
ERROR CODE (SELECT) =END-OF-ROW check failed
ERROR SQL STM (SELECT) =select * from test_tab where f1>=:f      and f1<=:f*2
ERROR VAR INFO (SELECT) =

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