#include <iostream>
#include <pqxx/pqxx>
int main()
try
{
// using namespace pqxx;
// spojeni s DB "dbname=sqlquiz host=localhost user=aaa password=bbb"
pqxx::connection conn("dbname=test");
// transakce
pqxx::work tran(conn, "demo-transaction");
// sql prikazy
pqxx::result r1(tran.exec("SET search_path TO pokus;"));
pqxx::result r2(tran.exec("INSERT into abc (x, y) "
" SELECT coalesce(max(x),0)+1, random() FROM abc ;"));
pqxx::result r3(tran.exec("SELECT * FROM abc;"));
// pruchod vyslednou tabulkou
if (r3.empty())
std::cout << "tabulka je prazdna\n";
else
std::cout << "tabulka ma "
<< r3.columns() << " sloupce a "
<< r3.size() << " radku\n\n";
for (pqxx::result::const_iterator i=r3.begin(); i!=r3.end(); ++i)
{
// sloupce muzeme adresovat absolutne nebo jmenem
std::cout << "x = " << i[0].as(std::string()) << " "
<< "y = " << i["y"].as(double())
<< std::endl;
}
// commit transakce, neni nutny pokud pracujeme pouze se selekty
tran.commit();
}
catch(...)
{
std::cerr << "demo : exception ...\n";
}