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cDatabase.h

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/******************************************************************************/
/*                                                                            */
/* POLiTe - Persistent Object Library Test                                    */
/*                                        Ph.D. Thesis by Mgr. Michal Kopecky */
/*                                                                            */
/* Charles University Prague                                                  */
/*                                                                            */
/******************************************************************************/
/*                                                                            */
/* File name: ... cDatabase.h                                                 */
/* Module: ...... Database Abstraction Layer                                  */
/*                                                                            */
/******************************************************************************/

#ifndef __C_DATABASE_H__
#define __C_DATABASE_H__

// Standard Header(s)
#include <fstream.h>

// Common POLiTe Header(s)
#include <lDefs.h>
#include <lExceptions.h>

class DLL_External Database
{
#ifdef POLITE_TEST_FRIEND
        friend POLITE_TEST_FRIEND;
#endif // POLITE_TEST_FRIEND

friend class Connection;
friend class ObjectBuffer;

protected:
        unsigned short _Strategies;
        char *_ConnectString;
        class Connection *_Connections[MAX_CONNECTION_PER_DATABASE];
        int _FreeConnections[MAX_CONNECTION_PER_DATABASE];
        int _FirstFreeConnection;
        static class Connection *_AllConnections[MAX_CONNECTION];
        static int _FreeAllConnections[MAX_CONNECTION];
        static int _FirstFreeAllConnection;

        bool _FindFreeConnectionHandles(int &LocHandle, int &GlobHandle);
        void _DisposeConnectionHandles(int &LocHandle, int &GlobHandle);

        virtual bool _Commit();
        virtual bool _Rollback();

public:
        Database(const char * const ConnectString = NULL);
        ~Database();

        virtual bool Assign(const char *ConnectString);
        virtual bool Commit();
        virtual bool Rollback();
        virtual class Connection *Connect(
                const char *UserName,
                const char *Password
                ) = 0;

        virtual bool WriteDDL(ofstream &S) = 0;
        // generates DDL stements nedded for the library to run
        virtual char *ColumnTypeDDL(char coltype, int collen) = 0;
        // returns correct database column type for given attribute type

        // Get and set corresponging patrs of attribute _Strategies
        // that holds all concurency strategies
        virtual enum UpdatingStrategy CurrentUpdatingStrategy() const
        // Returns Update Strategy part of attribute _Strategies
        {
                return (enum UpdatingStrategy)(_Strategies & US_MASK);
        };
        virtual bool SetUpdatingStrategy(enum UpdatingStrategy anUpdateStrategy);
        virtual enum WaitingStrategy CurrentWaitingStrategy() const
        {
                return (enum WaitingStrategy)(_Strategies & WS_MASK);
        };
        virtual bool SetWaitingStrategy(enum WaitingStrategy aWaitingStrategy);
        virtual enum LockingStrategy CurrentLockingStrategy() const
        {
                return (enum LockingStrategy)(_Strategies & LS_MASK);
        };
        virtual bool SetLockingStrategy(enum LockingStrategy aLockingStrategy);
        virtual enum ReadingStrategy CurrentReadingStrategy() const
        {
                return (enum ReadingStrategy)(_Strategies & RS_MASK);
        };
        virtual bool SetReadingStrategy(enum ReadingStrategy aReadingStrategy);

};

#endif //__GC_DATABASE_H__

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