OTL 4.0, Example 204 (otl_datetime container with TIMESTAMP values down to microseconds in Oracle 9i, and std::optional<T>)

This example demonstrates simple INSERT/SELECT with Oracle 9i TIMESTAMPs and std::optional<otl_datetime> / otl_datetime.

Source Code

#include <iostream>
using namespace std;

#include <stdio.h>
#define OTL_ORA9I // Compile OTL 4.0/OCI9i

// Uncomment the line below in case of OCI8.1.7 that 
// used against Oracle 9i.
//#define OTL_ORA8I

#if (defined(__clang__) || defined(__GNUC__)) && defined(OTL_CPP_14_ON)
// enable OTL support for std::optional when clang or g++ is used and
// when -std=c++14 or higher switch is used
#define OTL_STREAM_WITH_STD_OPTIONAL_ON
#endif

#if defined(_MSC_VER) && (_MSC_VER>=1910) && defined(OTL_CPP_17_ON)
// VC++ 2017 or higher when /std=c++latest is used
#define OTL_STREAM_WITH_STD_OPTIONAL_ON
#endif

#define OTL_ORA_TIMESTAMP
#include <otlv4.h> // include the OTL 4.0 header file


#if (defined(__clang__) || defined(__GNUC__)) && defined(OTL_CPP_14_ON) \
&& defined(OTL_STREAM_WITH_STD_OPTIONAL_ON)
// for clang or g++, when they use -std=c++14 or higher
#include <experimental/optional>
#endif

#if defined(_MSC_VER) && (_MSC_VER>=1910) && defined(OTL_CPP_17_ON)
// VC++ 2017 or higher when /std=c++latest is used
#include <optional>
#endif

otl_connect db; // connect object

void insert(void)
// insert rows into table

 otl_stream o(3, // stream buffer size in logical rows.
              "insert into test_tab "
              "values(:f1<int>,:f2<timestamp>)", 
                 // INSERT statement
              db // connect object
             );

 otl_datetime tm;

 for(int i=1;i<=10;++i){
  tm.year=1998;
  tm.month=10;
  tm.day=19;
  tm.hour=23;
  tm.minute=12;
  tm.second=12;
  tm.frac_precision=6; // microseconds
  tm.fraction=123456;
#if (defined(__clang__) || defined(__GNUC__)) && defined(OTL_CPP_14_ON) \
&& defined(OTL_STREAM_WITH_STD_OPTIONAL_ON)
// for clang or g++, when they use -std=c++14 or higher
std::experimental::optional<otl_datetime> tm2;
if(i!=5)
tm2=tm;
o<<i<<tm2;
#elif defined(_MSC_VER) && (_MSC_VER>=1910) && defined(OTL_CPP_17_ON)
// VC++ 2017 or higher when /std=c++latest is used
std::optional<otl_datetime> tm2;
if(i!=5)
tm2=tm;
o<<i<<tm2;
#else
if(i!=5)
o<<i<<tm;
else
o<<i<<otl_null();
#endif
 }
}

void select(void)

 otl_stream i(5, // stream buffer size in logical rows
              "select * from test_tab",
                 // SELECT statement
              db // connect object
             ); 
 
#if (defined(__clang__) || defined(__GNUC__)) && defined(OTL_CPP_14_ON) \
&& defined(OTL_STREAM_WITH_STD_OPTIONAL_ON)
// for clang or g++, when they use -std=c++14 or higher
std::experimental::optional<int> f1;
std::experimental::optional<otl_datetime> f2;
#elif defined(_MSC_VER) && (_MSC_VER>=1910) && defined(OTL_CPP_17_ON)
// VC++ 2017 or higher when /std=c++latest is used
std::optional<int> f1;
std::optional<otl_datetime> f2;
#else
int f1=0;
otl_datetime f2;
#endif


 while(!i.eof()){ // while not end-of-data


#if (defined(__clang__) || defined(__GNUC__)) && defined(OTL_CPP_14_ON) \
&& defined(OTL_STREAM_WITH_STD_OPTIONAL_ON)
// for clang or g++, when they use -std=c++14 or higher
// Second's precision needs to be specified BEFORE the structure can be
// used either for writing or reading timestamp values, which have second's
// fractional part.
f2.emplace(otl_datetime());
f2->frac_precision=6; // microseconds
i>>f1>>f2;
cout<<"f1="<<*f1;
if(!f2)
cout<<", f2=NULL";
else
cout<<", f2="<<f2->month<<"/"<<f2->day<<"/"
<<f2->year<<" "<<f2->hour<<":"<<f2->minute<<":"
<<f2->second<<"."
<<f2->fraction;
#elif defined(_MSC_VER) && (_MSC_VER>=1910) && defined(OTL_CPP_17_ON)
// VC++ 2017 or higher when /std=c++latest is used
f2.emplace(otl_datetime());
f2->frac_precision=6; // microseconds
i>>f1>>f2;
cout<<"f1="<<*f1;
if(!f2)
cout<<", f2=NULL";
else
cout<<", f2="<<f2->month<<"/"<<f2->day<<"/"
<<f2->year<<" "<<f2->hour<<":"<<f2->minute<<":"
<<f2->second<<"."
<<f2->fraction;
#else
// Second's precision needs to be specified BEFORE the stucture can be
// used either for writnig or reading timestamp values, which have second's
// fractional part.
f2.frac_precision=6; // microseconds
i>>f1>>f2;
cout<<"f1="<<f1;
if(i.is_null())
cout<<", f2=NULL";
else
cout<<", f2="<<f2.month<<"/"<<f2.day<<"/"
<<f2.year<<" "<<f2.hour<<":"<<f2.minute<<":"
<<f2.second<<"."
<<f2.fraction;
#endif
cout<<endl;
}
 
}
int main()
{
 otl_connect::otl_initialize(); // initialize OCI environment
 try{

  db.rlogon("scott/tiger"); // connect to Oracle

  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 timestamp)"
    );  // 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 Oracle

 return 0;

}

Output

f1=1, f2=10/19/1998 23:12:12.123456
f1=2, f2=10/19/1998 23:12:12.123456
f1=3, f2=10/19/1998 23:12:12.123456
f1=4, f2=10/19/1998 23:12:12.123456
f1=5, f2=NULL
f1=6, f2=10/19/1998 23:12:12.123456
f1=7, f2=10/19/1998 23:12:12.123456
f1=8, f2=10/19/1998 23:12:12.123456
f1=9, f2=10/19/1998 23:12:12.123456
f1=10, f2=10/19/1998 23:12:12.123456


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Copyright 1996-2017, Sergei Kuchin, email: skuchin@gmail.com, skuchin@gmail.com .

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