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/***********************************************************************
store_if.cpp - Demonstrates Query::store_if(), showing only the rows
from the sample table with prime quantities. This isn't intended
to be useful, only to show how you can do result set filtering that
outstrips the power of SQL.
Copyright (c) 2005-2010 by Educational Technology Resources, Inc.
Others may also hold copyrights on code in this file. See the CREDITS
file in the top directory of the distribution for details.
This file is part of MySQL++.
MySQL++ is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
MySQL++ is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public
License along with MySQL++; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
USA
***********************************************************************/
#include "cmdline.h"
#include "printdata.h"
#include "stock.h"
#include <mysql++.h>
#include <iostream>
#include <math.h>
// Define a functor for testing primality.
struct is_prime
{
bool operator()(const stock& s)
{
if ((s.num == 2) || (s.num == 3)) {
return true; // 2 and 3 are trivial cases
}
else if ((s.num < 2) || ((s.num % 2) == 0)) {
return false; // can't be prime if < 2 or even
}
else {
// The only possibility left is that it's divisible by an
// odd number that's less than or equal to its square root.
for (int i = 3; i <= sqrt(double(s.num)); i += 2) {
if ((s.num % i) == 0) {
return false;
}
}
return true;
}
}
};
int
main(int argc, char *argv[])
{
// Get database access parameters from command line
mysqlpp::examples::CommandLine cmdline(argc, argv);
if (!cmdline) {
return 1;
}
try {
// Establish the connection to the database server.
mysqlpp::Connection con(mysqlpp::examples::db_name,
cmdline.server(), cmdline.user(), cmdline.pass());
// Collect the stock items with prime quantities
std::vector<stock> results;
mysqlpp::Query query = con.query();
query.store_if(results, stock(), is_prime());
// Show the results
print_stock_header(results.size());
std::vector<stock>::const_iterator it;
for (it = results.begin(); it != results.end(); ++it) {
print_stock_row(it->item.c_str(), it->num, it->weight,
it->price, it->sDate);
}
}
catch (const mysqlpp::BadQuery& e) {
// Something went wrong with the SQL query.
std::cerr << "Query failed: " << e.what() << std::endl;
return 1;
}
catch (const mysqlpp::Exception& er) {
// Catch-all for any other MySQL++ exceptions
std::cerr << "Error: " << er.what() << std::endl;
return 1;
}
return 0;
}
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