This example demonstrates how otl_read_from_stream() / otl_write_to_stream() template functions can be used with STL containers (vectors, sets, maps, etc.).
#include <iostream>
#include <vector>
#include <set>
#include <map>
#include <iterator>
#include <string>
#define OTL_ODBC_MSSQL_2008 // Compile OTL 4/MS SQL SNAC
#define OTL_STL // Turn on STL features
#ifndef OTL_ANSI_CPP
#define OTL_ANSI_CPP // Turn on ANSI C++ typecasts
#endif
#include <otlv4.h> // include the OTL 4 header file
using namespace std;
otl_connect db; // connect object
// my row class
class my_row_class{
public:
int f1;
string f2;
// default constructor
my_row_class():f1(0),f2(){}
// general purpose constructor
my_row_class(const int af1, const string& af2):f1(af1),f2(af2){}
// destructor
~my_row_class(){}
// copy constructor
my_row_class(const my_row_class& row):f1(row.f1),f2(row.f2){}
// copy assignment operator
my_row_class& operator=(const my_row_class& row)
{
f1=row.f1;
f2=row.f2;
return *this;
}
#if defined(OTL_CPP_11_ON) || defined(_MSC_VER) && (_MSC_VER >= 1600)
// when move constructors / assignment operators are supported
my_row_class(my_row_class&& r):f1(r.f1),f2(move(r.f2)){}
my_row_class& operator=(my_row_class&& r)
{
f1=r.f1;
f2=move(r.f2);
return *this;
}
#endif
};
// "less-than" functor for "my set"
class my_set_less_than{
public:
bool operator()(const my_row_class& row1, const my_row_class& row2) const
{
if(row1.f1<row2.f1)
return true;
else
return false;
}
};
// various STL containers
typedef vector<my_row_class> my_vector_type;
typedef map<int,string,less<int> > my_map_type;
typedef set<my_row_class,my_set_less_than> my_set_type;
// redefined operator>> for reading my_row_class& from otl_stream
otl_stream& operator>>(otl_stream& s, my_row_class& row)
{
s>>row.f1>>row.f2;
return s;
}
// redefined operator<< for writing const my_row_class& into
// otl_stream
otl_stream& operator<<(otl_stream& s, const my_row_class& row)
{
s<<row.f1<<row.f2;
return s;
}
// redefined operator>> for reading my_map_type::value_type& from
// otl_stream
otl_stream& operator>>(otl_stream& s, my_map_type::value_type& row)
{
// std::map's key is const, which needs to be cast away
s>>const_cast<int&>(row.first);
s>>row.second;
return s;
}
// redefined operator<< for writing const my_map_type::value_type&
// into otl_stream
otl_stream& operator<<(otl_stream& s, const my_map_type::value_type& row)
{
s<<row.first<<row.second;
return s;
}
void insert() // insert rows into table { otl_stream o(50, // buffer size
"insert into test_tab values(:f1<int>,:f2<char[31]>)",
// SQL statement
db // connect object
);
my_vector_type vo; // vector of rows
my_set_type so; // set of rows
my_map_type mo; // map of pairs<int,string>
// populate the vector
for(int i=1;i<=3;++i)
vo.push_back(my_row_class(i,"NameXXX"));
// insert the vector into the table
otl_write_to_stream(vo.begin(),vo.end(),o);
// populate the set
for(int i=4;i<=6;++i)
so.insert(my_row_class(i,"NameXXX"));
// insert the set into the table
otl_write_to_stream(so.begin(),so.end(),o);
// populate the set
for(int i=7;i<=10;++i)
mo[i]="NameXXX";
// insert the map into the table
otl_write_to_stream(mo.begin(),mo.end(),o);
} void select() { otl_stream i(50, // buffer size
"select * from test_tab where f1>=:f1<int> and f1<=:f11<int>*2",
// SELECT statement
db // connect object
);
// create select stream
my_vector_type v; // vector of rows
my_set_type s; // set of rows
my_map_type m;
// assigning :f1 = 4, :f11 = 4, and triggering an execution of the
// SELECT statement
i<<4<<4;
// read all rows to be fetched into the vector
otl_read_from_stream(i,back_inserter(v));
// print out the content of the vector
for(my_vector_type::const_iterator x=v.begin(); x!=v.end(); ++x)
cout<<"F1="<<(*x).f1<<", F2="<<(*x).f2<<endl;
cout<<"==========================="<<endl;
// assigning :f1 = 4, :f11 = 4, and triggering an execution of the
// SELECT statement
i<<4<<4;
// read all rows to be fetched into the set
otl_read_from_stream(i,inserter(s,s.end()));
// print out the content of the set
for(my_set_type::const_iterator x=s.begin(); x!=s.end(); ++x)
cout<<"F1="<<(*x).f1<<", F2="<<(*x).f2<<endl;
cout<<"==========================="<<endl;
// assigning :f1 = 4, :f11 = 4, and triggering an execution of the
// SELECT statement
i<<4<<4;
// read all rows to be fetched into the set
otl_read_from_stream(i,inserter(m,m.end()));
// print out the content of the set
for(my_map_type::const_iterator x=m.begin(); x!=m.end(); ++x)
cout<<"FIRST="<<(*x).first<<", SECOND="<<(*x).second<<endl;
cout<<"==========================="<<endl;
} int main() { otl_connect::otl_initialize(); // initialize the database API environment try{ db.rlogon("scott/tiger@mssql2008"); // 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 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; }
F1=4, F2=NameXXX
F1=5, F2=NameXXX
F1=6, F2=NameXXX
F1=7, F2=NameXXX
F1=8, F2=NameXXX
===========================
F1=4, F2=NameXXX
F1=5, F2=NameXXX
F1=6, F2=NameXXX
F1=7, F2=NameXXX
F1=8, F2=NameXXX
===========================
FIRST=4, SECOND=NameXXX
FIRST=5, SECOND=NameXXX
FIRST=6, SECOND=NameXXX
FIRST=7, SECOND=NameXXX
FIRST=8, SECOND=NameXXX
===========================
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