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114 lines
3.7 KiB
C++
114 lines
3.7 KiB
C++
/* Copyright (C) 2003 MySQL AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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/*****************************************************************************
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* Name: NdbResultSet.hpp
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* Include:
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* Link:
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* Author: Martin Sköld
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* Date: 2002-04-01
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* Version: 0.1
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* Description: Cursor class
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* Documentation:
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* Adjust: 2002-04-01 Martin Sköld First version.
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****************************************************************************/
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#ifndef NdbResultSet_H
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#define NdbResultSet_H
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#include <NdbCursorOperation.hpp>
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#include <NdbIndexOperation.hpp>
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#include <NdbScanOperation.hpp>
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/**
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* @class NdbResultSet
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* @brief NdbResultSet contains a NdbCursorOperation.
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*/
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class NdbResultSet
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{
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friend class NdbCursorOperation;
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public:
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/**
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* Get the next tuple in a scan transaction.
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*
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* After each call to NdbResult::nextResult
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* the buffers and NdbRecAttr objects defined in
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* NdbOperation::getValue are updated with values
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* from the scanned tuple.
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*
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* @param fetchAllowed If set to false, then fetching is disabled
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*
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* The NDB API will contact the NDB Kernel for more tuples
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* when necessary to do so unless you set the fetchAllowed
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* to false.
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* This will force NDB to process any records it
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* already has in it's caches. When there are no more cached
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* records it will return 2. You must then call nextResult
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* with fetchAllowed = true in order to contact NDB for more
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* records.
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*
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* fetchAllowed = false is useful when you want to update or
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* delete all the records fetched in one transaction(This will save a
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* lot of round trip time and make updates or deletes of scanned
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* records a lot faster).
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* While nextResult(false)
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* returns 0 take over the record to another transaction. When
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* nextResult(false) returns 2 you must execute and commit the other
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* transaction. This will cause the locks to be transferred to the
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* other transaction, updates or deletes will be made and then the
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* locks will be released.
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* After that, call nextResult(true) which will fetch new records and
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* cache them in the NdbApi.
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*
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* @note If you don't take over the records to another transaction the
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* locks on those records will be released the next time NDB Kernel
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* is contacted for more records.
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*
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* @note Please contact for examples of efficient scan
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* updates and deletes.
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*
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* @note See ndb/examples/ndbapi_scan_example for usage.
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*
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* @return
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* - -1: if unsuccessful,<br>
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* - 0: if another tuple was received, and<br>
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* - 1: if there are no more tuples to scan.
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* - 2: if there are no more cached records in NdbApi
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*/
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int nextResult(bool fetchAllowed = true);
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void close();
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NdbOperation* updateTuple();
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NdbOperation* updateTuple(NdbConnection* takeOverTransaction);
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int deleteTuple();
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int deleteTuple(NdbConnection* takeOverTransaction);
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private:
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NdbResultSet(NdbCursorOperation*);
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~NdbResultSet();
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void init();
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NdbCursorOperation* m_operation;
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};
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#endif
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