database.h

См. документацию.

#ifndef DATABASE_H
#define DATABASE_H
 
#include <QSqlDatabase>
 
class Database;
 
class DatabaseDestroyer
{
    private:
        Database * pInstance;
    public:
        ~DatabaseDestroyer() {
            delete this->pInstance;
        }
        void initialize(Database *p) {
            this->pInstance = p;
        }
};

class Database {
    private:
        static Database * pInstance;
        void initDB();
        static QSqlDatabase dbInstance;
        static DatabaseDestroyer destroyer;
    protected:
        Database();
        Database(const Database&) = delete;
        Database& operator = (Database &)=delete;
        ~Database();
        friend class DatabaseDestroyer;
    public:
        static Database* getInstance() {
            if (!pInstance) {
                pInstance = new Database();
                destroyer.initialize(pInstance);
            }
            return pInstance;
        }

        QSqlQuery doSQLQuery(QString stringQuery);
};
 
 
 
#endif // DATABASE_H