Files
secondo/Algebras/BasicEngine/ResultIteratorMySQL.cpp
2026-01-23 17:03:45 +08:00

76 lines
1.9 KiB
C++

/*
----
This file is part of SECONDO.
Copyright (C) 2021,
Faculty of Mathematics and Computer Science,
Database Systems for New Applications.
SECONDO is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
SECONDO 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with SECONDO; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
----
//[$][\$]
*/
#include "ResultIteratorMySQL.h"
namespace BasicEngine {
/*
1.1 Is a new tuple available in the iterator
*/
bool ResultIteratorMySQL::hasNextTuple() {
return currentTuple < totalTuples;
}
/*
1.2 Return the next tuple from the iterator
*/
Tuple* ResultIteratorMySQL::getNextTuple() {
Tuple* result = basicTuple->Clone();
MYSQL_ROW row = mysql_fetch_row(res);
if(row == nullptr) {
BOOST_LOG_TRIVIAL(error) <<
"Unable to fetch next row from MySQL result";
totalTuples = currentTuple;
return nullptr;
}
for(size_t i = 0; i < attributeInstances.size(); i++) {
Attribute* attr = attributeInstances[i]->Clone();
if(! row[i]) {
attr->SetDefined(false);
} else {
char* value = row[i];
attr->ReadFromString(value);
attr->SetDefined(true);
}
result->PutAttribute(i, attr);
}
currentTuple++;
return result;
}
}; // End namespace