/*
This file is part of the KDB libraries
Copyright (c) 2000 Praduroux Alessandro <pradu@thekompany.com>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later version.
This library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.
*/
#ifndef KDB_CONNECTOR_H
#define KDB_CONNECTOR_H "$Id: connector.h,v 1.6 2001/02/01 03:15:49 garbanzo Exp $"
#include <qstring.h>
#include <qstringlist.h>
#include <kdb/exception.h>
#include <kdb/object.h>
#include <kdb/kdb.h>
namespace KDB {
class Exception;
class Handler;
class Table;
class Field;
class Query;
/**
* @short base interaction class for plugins.
*
* This is the base class for the interaction between kdbcore and
* the various plugins. It should be subclassed by plugins, but should
* not be used by the client programs
*
*
* @author Alessandro Praduroux <pradu@thekompany.com>
* @version kdbcore 0.0.2
*/
class Connector :
public Object {
public:
Connector();
Connector(const Connector& c);
virtual ~Connector();
// virtual methods: must be overridden in the subclass
/**
* closes the connection to the database backend
*/
virtual void close();
/**
* opens the connection to the database backend
*/
virtual bool connect() = 0;
/**
* returns the list of the available databases
* for the current open connection
*/
virtual QStringList databases() = 0;
/**
* returns the list of the available tables
* for the current open database
*/
virtual QStringList tables() = 0;
/**
* returns the list of the fields for the given table
* for the current open database. The rows must contain:
*
* @li field name
* @li datatype, native form
* @li size, where applicable
* @li precision, where applicable
* @li Null constraint (Y/N)
* @li Default value
* @li referential constraint
* @li comment
*
* the only mandatory fields are field name, datatype and size. All
* other values can be present if the DBMS is able to give them
*/
virtual RowList fields(const QString & tableName) = 0;
/**
* executes an SQL statement. The return value is the number of
* rows affected by the statement
*/
virtual KDB_ULONG execute(const QString &sql) = 0;
/**
* creates an empty database
*/
virtual bool createDatabase(const QString & name) = 0;
/**
* drops a database with all its content
*/
virtual bool dropDatabase(const QString & name) = 0;
/**
* creates a table with the characteristic of the given one
*/
virtual bool createTable(const Table & tab) = 0;
/**
* remove a table in the currend database deleting all its content
*/
virtual bool dropTable(const QString & name) = 0;
/**
* append a file to a table. the underlying DBMS must issue an alter here
*/
virtual bool appendField(const QString &table, Field *f) = 0;
/**
* remove a field from a table. the underlying DBMS must issue an alter here
*/
virtual bool removeField(const QString &table, const QString &field) = 0;
/**
* change the definition of a field of the given table. the underlying DBMS
* must issue an alter here
*/
virtual bool changeField(const QString &table, Field *f) = 0;
/**
* clones the current object. If the object holds an open connection,
* the resulting connector must be open too.
*/
virtual Connector * clone() = 0;
/**
* set the operational database for the current connector. From this
* point all the methods will affect the selected database
*/
virtual bool setCurrentDatabase(const QString &name) = 0;
/**
* returns the corresponding KDB datatype for the given native one
*/
virtual DataType nativeToKDB(const QString &type) = 0;
/**
* returns the corresponding native datatype for the given KDB one
*/
virtual QString KDBToNative(DataType type) = 0;
/**
* executes a select to the backend and returns an handler to the
* result
*/
virtual Handler *query(const QString &SQL) = 0;
/**
* Create a query object. Plugins can override some functions of the class Query to take
* advantage of some specific optimizations. This is entirely optional, default implementations
* with a meaningful behaviour are provided in the kdedb core library
*/
virtual Query *createQueryObject(QObject *parent = 0L,
const char *name = 0L,
const QString &sql = QString::null);
/**
* start a transaction for the current connection
* an error is raised if the underlying DBMS does not support
* transactions
*/
virtual void beginTransaction() = 0;
/**
* end the current transaction and save all the changes to the
* database.
* an error is raised if the underlying DBMS does not support
* transactions or if there isn't any transaction started
*/
virtual void commit() = 0;
/**
* end the current transaction and drop all changes made up to now.
* an error is raised if the underlying DBMS does not support
* transactions or if there isn't any transaction started
*/
virtual void rollback() = 0;
// nonvirtual methods
/// @internal
void setHost(const QString & host);
/// @internal
void setPort(int port);
/// @internal
void setUser(const QString & user);
/// @internal
void setPassword(const QString & pwd);
/// @internal
QString host() const;
/// @internal
int port() const;
/// @internal
QString user() const;
/// @internal
QString password() const;
/// @internal
bool isConnected() const;
protected:
/**
* must be called by subclasses when a connection to the backend
* is established
*/
void setConnected(bool conn);
private:
QString _host;
int _port;
QString _user;
QString _pwd;
bool _connected;
};
};
#endif
| Generated by: root@powerpc.ports.openbsd.org on Tue Apr 24 23:01:57 2001, using kdoc 2.0a53. |