/*********************************************************************** 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 #include #include // 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 results; mysqlpp::Query query = con.query(); query.store_if(results, stock(), is_prime()); // Show the results print_stock_header(results.size()); std::vector::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; }