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/*
* The Mana Server
* Copyright (C) 2004-2010 The Mana World Development Team
*
* This file is part of The Mana Server.
*
* The Mana Server 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
* any later version.
*
* The Mana Server 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 The Mana Server. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef DATA_PROVIDER_H
#define DATA_PROVIDER_H
#include <string>
#include <stdexcept>
#include "recordset.h"
namespace dal
{
class DataProvider;
/**
* Enumeration type for the database backends.
*/
typedef enum {
DB_BKEND_MYSQL,
DB_BKEND_SQLITE,
DB_BKEND_POSTGRESQL
} DbBackends;
/**
* Begins a transaction on a given data provider. When the transaction is
* complete, commit() should be called. When the destructor is called before
* commit() is called, the transaction is rolled back.
*
* This avoids having to remember to call rollback in a lot of places, and
* makes exception handling easier.
*/
class PerformTransaction
{
public:
PerformTransaction(DataProvider *dataProvider);
~PerformTransaction();
void commit();
private:
DataProvider *mDataProvider;
bool mTransactionStarted;
bool mCommitted;
};
/**
* An abstract data provider.
*
* Notes:
* - depending on the database backend, the connection to an unexisting
* database may actually create it as a side-effect (e.g. SQLite).
*
* Limitations:
* - this class does not provide APIs for:
* - remote connections,
* - creating new databases,
* - dropping existing databases.
*/
class DataProvider
{
public:
DataProvider()
throw();
virtual ~DataProvider()
throw();
bool isConnected() const
throw();
/**
* Get the name of the database backend.
*
* @return the database backend name.
*/
virtual DbBackends getDbBackend() const
throw() = 0;
/**
* Create a connection to the database.
*
* Each dataprovider is responsible to have default values and load
* necessary options from the config file.
*
* @exception DbConnectionFailure if unsuccessful connection.
*/
virtual void connect() = 0;
/**
* Execute a SQL query.
*
* @param sql the SQL query.
* @param refresh if true, refresh the cache (default = false).
*
* @return a recordset.
*
* @exception DbSqlQueryExecFailure if unsuccessful execution.
* @exception std::runtime_error if trying to query a closed database.
*/
virtual const RecordSet&
execSql(const std::string& sql,
const bool refresh = false) = 0;
/**
* Close the connection to the database.
*
* @exception DbDisconnectionFailure if unsuccessful disconnection.
*/
virtual void disconnect() = 0;
std::string getDbName() const;
/**
* Starts a transaction.
*
* @exception std::runtime_error if a transaction is still open
*/
virtual void beginTransaction()
throw (std::runtime_error) = 0;
/**
* Commits a transaction.
*
* @exception std::runtime_error if no connection is currently open.
*/
virtual void commitTransaction()
throw (std::runtime_error) = 0;
/**
* Rollback a transaction.
*
* @exception std::runtime_error if no connection is currently open.
*/
virtual void rollbackTransaction()
throw (std::runtime_error) = 0;
/**
* Returns whether the data provider is currently in a transaction.
*/
virtual bool inTransaction() const = 0;
/**
* Returns the number of changed rows by the last executed SQL
* statement.
*
* @return Number of rows that have changed.
*/
virtual unsigned getModifiedRows() const = 0;
/**
* Returns the last inserted value of an autoincrement column after an
* INSERT statement.
*
* @return last autoincrement value.
*/
virtual unsigned getLastId() const = 0;
/**
* Prepare SQL statement
*/
virtual bool prepareSql(const std::string &sql) = 0;
/**
* Process SQL statement
* SQL statement needs to be prepared and parameters binded before
* calling this function
*/
virtual const RecordSet& processSql() = 0;
/**
* Bind Value (String)
* @param place - which parameter to bind to
* @param value - the string to bind
*/
virtual void bindValue(int place, const std::string &value) = 0;
/**
* Bind Value (Integer)
* @param place - which parameter to bind to
* @param value - the integer to bind
*/
virtual void bindValue(int place, int value) = 0;
protected:
std::string mDbName; /**< the database name */
bool mIsConnected; /**< the connection status */
std::string mSql; /**< cache the last SQL query */
RecordSet mRecordSet; /**< cache the result of the last SQL query */
};
} // namespace dal
#endif // DATA_PROVIDER_H
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