# OTL 4.0, Example 405 (otl_value<T>, ODBC / Sybase SQL Server)

This example demonstrates OTL streams and otl_value<T>.

## Source Code

    #include <iostream>
    #include <string>

    #define OTL_ODBC_UNIX // Compile OTL 4.0/ODBC
    #define OTL_STL // Turn on STL features and otl_value<T>
    #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

    void insert()
    // insert rows into table
    {
     otl_stream o(50, // buffer size
                  "insert into test_tab "
                  "values(:f1<int>,:f2<char[31]>,:f3<timestamp>)",
                     // SQL statement
                  db // connect object
                 );

     otl_value<string> f2; // otl_value container of STL string
     otl_value<otl_datetime> f3; // container of otl_datetime

     for(int i=1;i<=100;++i){

      if(i%2==0)
       f2="NameXXX";
      else
       f2=otl_null(); // Assign otl_null() to f2

      if(i%3==0){
       // Assign a value to f3 via the .v field directly
       f3.v.year=2001;
       f3.v.month=1;
       f3.v.day=1;
       f3.v.hour=13;
       f3.v.minute=10;
       f3.v.second=5;
       f3.set_non_null(); // Set f3 as a "non-NULL"
      }else
       f3.set_null(); // Set f3 as null via .set_null() function

      o<<i<<f2<<f3;

     }
    }

    void select()
    {
     otl_stream i(50, // buffer size
                  "select * from test_tab where f1>=:f11<int> and f1<=:f12<int>*2",
                     // SELECT statement
                  db // connect object
                 );
       // create select stream

     int f1;
     otl_value<string> f2;
     otl_value<otl_datetime> f3;

     i<<8<<8; // assigning :f11, :f12 = 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>>f3;
      cout<<"f1="<<f1<<", f2="<<f2<<", f3="<<f3<<endl;
     }

     i<<4<<4; // assigning :f11, :f12 = 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>>f3;
      cout<<"f1="<<f1<<", f2="<<f2<<", f3="<<f3<<endl;
     }

    }

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

      db.rlogon("scott/tigger@sybsql"); // connect to MS SQL Server

      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), f3 datetime)"
        );  // 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.sqlstate<<endl; // print out SQLSTATE message
      cerr<<p.var_info<<endl; // print out the variable that caused the error
     }

     db.logoff(); // disconnect from MS SQL Server

     return 0;

    }

## Output

    f1=8, f2=NameXXX, f3=NULL
    f1=9, f2=NULL, f3=1/1/2001 13:10:5
    f1=10, f2=NameXXX, f3=NULL
    f1=11, f2=NULL, f3=NULL
    f1=12, f2=NameXXX, f3=1/1/2001 13:10:5
    f1=13, f2=NULL, f3=NULL
    f1=14, f2=NameXXX, f3=NULL
    f1=15, f2=NULL, f3=1/1/2001 13:10:5
    f1=16, f2=NameXXX, f3=NULL
    f1=4, f2=NameXXX, f3=NULL
    f1=5, f2=NULL, f3=NULL
    f1=6, f2=NameXXX, f3=1/1/2001 13:10:5
    f1=7, f2=NULL, f3=NULL
    f1=8, f2=NameXXX, f3=NULL

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

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