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/* 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
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