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