# OTL 4.0, Example 137 (std::string, STL-compliant stream iterators)

# Example 137 (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/
    // #define OTL_ODBC_UNIX // uncomment this line if UnixODBC is used
    #define OTL_STL // Turn on STL features
    #define OTL_ANSI_CPP // Turn on ANSI C++ typecasts
    #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& row)
     {
      f1=row.f1;
      f2=row.f2;
     }

    // assignment operator
     row& operator=(const row& row)
     {
      f1=row.f1;
      f2=row.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& row)
    {
     s<<"f1="<<row.f1<<", f2="<<row.f2;
     return s;
    }

    void insert()
    // insert rows into table
    {
     otl_stream o(1, // buffer size should be == 1 on INSERT
                  "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="<<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="<<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("UID=scott;PWD=tiger;DSN=ib6sql"); // connect to ODBC
    //  db.rlogon("scott/tiger@ib6sql"); // connect to ODBC, alternative format
                                        // of connect string

      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

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

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