OTL 4.0, Example 281 (std::string, STL-compliant stream iterators)

This example demonstrates STL-compliant OTL stream iterators, std::strings, and ANSI C++ typecasts.

Source Code

#include <iostream>
#include <vector>
#include <iterator>
#include <string>
#include <cstring>
#include <cstdlib>

#define OTL_ODBC // Compile OTL 4.0/ODBC
#define ODBCVER 0x0250 // ODBC Version # needs to be downgraded
                       // to 2.5 because the SQLite ODBC driver seems
                       // to run slower when ODBC 3.x functions
                       // used (performance is not as good as with
                       // ODBC 2.5 function calls)
// #define OTL_ODBC_UNIX // uncomment this line if UnixODBC is used
#define OTL_STL // Turn on STL features
#include <otlv4.h> // include the OTL 4.0 header file

using namespace std;

otl_connect db; // connect object

// row container class
class row{
public:
 int f1;
 string f2;

// default constructor
 row(){f1=0;}

// destructor
 ~row(){}

// copy constructor
 row(const row& arow)
 {
  f1=arow.f1;
  f2=arow.f2;
 }
 
// assignment operator
 row& operator=(const row& arow)
 {
  f1=arow.f1;
  f2=arow.f2;
  return *this;
 }

};

// redefined operator>> for reading row& from otl_stream
otl_stream& operator>>(otl_stream& s, row& row)
{
 s>>row.f1>>row.f2;
 return s;
}

// redefined operator<< for writing row& into otl_stream
otl_stream& operator<<(otl_stream& s, const row& row)
{
 s<<row.f1<<row.f2;
 return s;
}

// redefined operator<< writing row& into ostream
ostream& operator<<(ostream& s, const row& arow)
{
 s<<"f1="<<arow.f1<<", f2="<<arow.f2;
 return s;
}

void insert()
// insert rows into table
{ 
 otl_stream 
   o(30, // buffer size
     "insert into test_tab values(:f1<int>,:f2<char[31]>)", 
         // INSERT statement
     db // connect object
    );

 row r; // single row buffer
 vector<row> vo; // vector of rows

// populate the vector
 for(int i=1;i<=100;++i){
  r.f1=i;
  r.f2="NameXXX";
  vo.push_back(r);
 }

 cout<<"vo.size="<<(int)vo.size()<<endl;
// insert vector into table
 copy(vo.begin(), 
      vo.end(), 
      otl_output_iterator<row>(o)
     );
}

void select(const int af1)
{ 
 otl_stream i(50, // buffer size may be > 1
              "select * from test_tab "
              "where f1 between :f11<int> and :f12<int>*2",
              db // connect object
             ); 
   // create select stream
 
 vector<row> v; // vector of rows

 i<<af1<<af1; // enter :f11=8 and :f12=8 into the stream

// copy all rows to be fetched into the vector

 copy(otl_input_iterator<row,ptrdiff_t>(i), 
      otl_input_iterator<row,ptrdiff_t>(),
      back_inserter(v));    

 cout<<"Size="<<(int)v.size()<<endl;

// send the vector to cout
 copy(v.begin(), v.end(), ostream_iterator<row>(cout, "\n"));

}

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

  db.rlogon("scott/tiger@sqlite");

  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

  db.commit(); // committing the create table statement to to the database

  insert(); // insert records into table
  select(8); // 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 ODBC

 return 0;

}

Output

vo.size=100
Size=9
f1=8, f2=NameXXX
f1=9, f2=NameXXX
f1=10, f2=NameXXX
f1=11, f2=NameXXX
f1=12, f2=NameXXX
f1=13, f2=NameXXX
f1=14, f2=NameXXX
f1=15, f2=NameXXX
f1=16, f2=NameXXX

Examples Contents Go Home

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.