Example 168 (otl_stream::clean(), cleaning the Result Set stream's error flags, MS SQL Server)

Source Code

#include <iostream>
using namespace std;

#include <stdio.h>

#define OTL_ODBC // Compile OTL 4.0/ODBC 
#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<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;
 }
}

void select()
{ 
 otl_stream i(50, // buffer size
              "{call my_proc(:f1<char[40],in>)}",
                 // implicit SELECT statement
              db, // connect object
              otl_implicit_select // implicit SELECT statement
             );
 
 float f1;
 char f2[31];
 
 try{
  cout<<"====> Starting a fetch sequence...."<<endl;
  i<<"xxx8"; // assigning :f1 = "xxx8", it's obviously 
             // invalid for a numeric column
    // 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;
  } 
 }catch(otl_exception& p){
  cerr<<"===> A database exception is caught: "<<endl;
  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
  cerr<<"===> Cleaning up the stream's error flags"<<endl;
  i.clean();
 }

 cout<<"====> Starting another fetch sequence..."<<endl;
 i<<"4"; // assigning :f1 = 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 the environment
 try{

  db.rlogon("scott/tiger@mssql"); // 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

  otl_cursor::direct_exec
   (
    db,
    "drop procedure my_proc",
    otl_exception::disabled // disable OTL exceptions
   ); // drop old version of stored procedure, if there is one.

  otl_cursor::direct_exec
   (db,
    "CREATE PROCEDURE my_proc "
    "  @F1 int "
    "AS "
    "SELECT * FROM test_tab "
    "WHERE f1>=@F1 AND f1<=@F1*2 "
   );  // create stored procedure

  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

====> Starting a fetch sequence....
===> A database exception is caught:
[Microsoft][ODBC SQL Server Driver][SQL Server]Error converting data 
type varchar to int.
{call my_proc(?               )}

===> Cleaning up the stream's error flags
====> Starting another fetch sequence...
f1=4, f2=Name4
f1=5, f2=Name5
f1=6, f2=Name6
f1=7, f2=Name7
f1=8, f2=Name8

Copyright © 1996, 2007, Sergei Kuchin, email: skuchin@ispwest.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.