dbmsappui.cpp

symbian基本的数据库编程,数据库的常用操作.

    {
    if(iBookDb && iBookDb->IsOpen())
        {
        iBookDb->Close();
        delete iBookDb;
        iBookDb = NULL;
        }
    ChangeViewL(EMainView);
    }


// ---------------------------------------------------------------------------
// CDBMSAppUi::ShowDBMSEditorView()
//
// Activate DBMS editor view
// ---------------------------------------------------------------------------
//
void CDBMSAppUi::ShowBookEditorViewL()
    {
    ChangeViewL(EEditorView);
    }


// ---------------------------------------------------------------------------
// CDBMSAppUi::AddDBMSL()
//
// Add a Book to database. Query details from DBMS editor view.
//
// There are two variants for insertion. See DBEngine.h fordetails.
// ---------------------------------------------------------------------------
//
void CDBMSAppUi::AddBookL(TBool aUseSql)
    {

    _LIT(KErrorMsg,"Failed. Make sure the fields are not empty.");
    TInt err(KErrNone);

    // Lengths are from DBEngine.h. Author uses default length (50)
    TBuf<50> author;
    TBuf<KTitleMaxLength> title;
    TBuf<KDescriptionMaxLength> description;
    

    iBookEditorView->GetAuthorL(author);
    iBookEditorView->GetTitleL(title);
    iBookEditorView->GetDescriptionL(description);

    if(aUseSql)
        err = iBookDb->AddBookWithSql(author,
                                            title,
                                            description);
    else
        err = iBookDb->AddBookWithCppApi(author,
                                               title,
                                               description);

    if(err)
        ShowNoteL(KErrorMsg);
    else
        ShowAllBooksL(); // Change back to listbox view
        
    }


// ---------------------------------------------------------------------------
// CDBMSAppUi::RemoveDBMSL()
//
// Remove selected Book from the database.
//
// Implementation removes named Book from the database. If there are multiple
// matches for the Book title, the are all removed.
// ---------------------------------------------------------------------------
//
void CDBMSAppUi::RemoveBookL()
    {

    TBuf<KBookItemMaxLength> selectedBookTitle;
    if(iListboxView->GetSelectedItem(selectedBookTitle) != KErrNone)
        {
        _LIT(KErrorMsg,"Failed. Book not selected.");
        ShowNoteL(KErrorMsg);
        return;
        }

    TInt resultCount;
    // Wildcards are also allowed, like 'Title*', or '?itle"
    iBookDb->RemoveBooks(selectedBookTitle, resultCount);
    ShowAllBooksL();
    }


// ---------------------------------------------------------------------------
// CDBMSAppUi::RemoveAllDBMSsL()
//
// Remove all Books from database.
// ---------------------------------------------------------------------------
//
void CDBMSAppUi::RemoveAllBooksL()
    {
    _LIT(KInfoText,"All Books removed.");
    TInt resultCount;
    iBookDb->RemoveAllBooks(resultCount);
    ShowNoteL(KInfoText);
    ShowAllBooksL();
    }


// ---------------------------------------------------------------------------
// CDBMSAppUi::UpdateDBMSTitleL()
//
// Change the title of a selected Book.
// ---------------------------------------------------------------------------
//
void CDBMSAppUi::UpdateBookTitleL()
    {
    _LIT(KQuery,"New title(s) for: ");
    TBuf<KBookItemMaxLength> selectedBookTitle;
    if(iListboxView->GetSelectedItem(selectedBookTitle) != KErrNone)
        {
        _LIT(KErrorMsg,"Failed. Book not selected.");
        ShowNoteL(KErrorMsg);
        return;
        }
    TBuf<KBookItemMaxLength+32> prompt;
    TBuf<KBookItemMaxLength> newTitle;

    prompt.Append(KQuery);
    prompt.Append(selectedBookTitle);

    if(QueryTextL(prompt, newTitle))
        {
        newTitle.Trim(); // Remove specific characters from the beginning
                         // and the end of the string
        iBookDb->UpdateBookTitle(selectedBookTitle, newTitle);
        ShowAllBooksL();
        }
    }


// ---------------------------------------------------------------------------
// CDBMSAppUi::ShowAllDBMSsL()
//
// Get list of all Books in the database. Show the titles in the listbox
// ---------------------------------------------------------------------------
//
void CDBMSAppUi::ShowAllBooksL()
    {
    _LIT(KAllBooksTitle,"Books in DBMS:");

    // Get array of full Book infos from the database. Construct array of
    // titles and show them in the listbox view.

    CDesCArrayFlat* Books = iBookDb->GetAllBooksL();
    CleanupStack::PushL(Books);
    CDesCArrayFlat* titles = TitlesArrayL(Books);
    CleanupStack::PushL(titles);

    ChangeViewL(EListView); // construct the listbox view
    iListboxView->SetCaptionL(KAllBooksTitle);
    CleanupStack::Pop(titles);
    iListboxView->SetListItemsL(titles); // Takes ownership
    CleanupStack::PopAndDestroy(Books);

    }


// ---------------------------------------------------------------------------
// CDBMSAppUi::SearchBooksL()
//
// Query Book search string from the user and perform Book search. Show the
// results in the list.
//
// Implementation finds Books according to a KBooksTitleCol column name
// and the queried search pattern.
// ---------------------------------------------------------------------------
//
void CDBMSAppUi::SearchBooksL()
    {
    _LIT(KSearchResult, "Search result:");
    _LIT(KBookSearch, "Book search");
    _LIT(KWildCard, "*");

    TBuf<KTitleMaxLength> titlePattern;
    TBuf<32> prompt(KBookSearch);

    QueryTextL(prompt, titlePattern);
    titlePattern.Append(KWildCard);

    ChangeViewL(EListView);
    iListboxView->SetCaptionL(KSearchResult);

    // Get array of matching DBMSs. Construct array of titles from the
    // DBMSs array and show it in the listbox view.

    CDesCArrayFlat* Books =
        iBookDb->GetBooksByKeyL(KBooksTitleCol, titlePattern);
    CleanupStack::PushL(Books);

    CDesCArrayFlat* titles = TitlesArrayL(Books);
    iListboxView->SetListItemsL(titles); // Takes ownership

    CleanupStack::PopAndDestroy(Books);
    }


// ---------------------------------------------------------------------------
// CDBMSAppUi::IndexFindL()
//
// Find a Book using index. Show full info for the Book.
// ---------------------------------------------------------------------------
//
void CDBMSAppUi::IndexFindL()
    {
    _LIT(KDetailsCaption,"Book details:");

    // Query the title of the selected Book in the listbox
    TBuf<KBookItemMaxLength> selectedBook;
    if(iListboxView->GetSelectedItem(selectedBook) != KErrNone)
    {
        _LIT(KErrorMsg,"Failed. Book not selected.");
        ShowNoteL(KErrorMsg);
        return;
    }

    // Query Book details from the database using Book title
    TBuf<KBookItemMaxLength> result;
    TInt err = iBookDb->GetABookFast(selectedBook, result);
    if(err==KErrNotFound)
        {
        _LIT(KNotFoundMsg,"Book not found.");
        ShowNoteL(KNotFoundMsg);
        return;
        }
    iEikonEnv->InfoWinL(KDetailsCaption, result);
    }


// ---------------------------------------------------------------------------
// CDBMSAppUi::AddDateColumn()
//
// Adds a date column to the Books table - if the column does not exist already
// ---------------------------------------------------------------------------
//
void CDBMSAppUi::AddDateColumnL()
    {
        iBookDb->AddDateColumn();
        ShowColumnsL();
    }


// ---------------------------------------------------------------------------
// CDBMSAppUi::RemoveDateColumnL()
//
// Removes the date column from Books table - if the column exists
// ---------------------------------------------------------------------------
//
void CDBMSAppUi::RemoveDateColumnL()
    {
        iBookDb->RemoveDateColumn();
        ShowColumnsL();
    }


// ---------------------------------------------------------------------------
// CDBMSAppUi::ShowColumns()
//
// Show the columns of the Book (Books table)
// ---------------------------------------------------------------------------
//
void CDBMSAppUi::ShowColumnsL()
    {
    _LIT(KColumnsCaption,"Columns in Book:");
    ChangeViewL(EColumnsView); // construct the listbox view
    iListboxView->SetCaptionL(KColumnsCaption);
    CDesCArrayFlat* tmp = iBookDb->ColumnNamesAndSizesL();
    iListboxView->SetListItemsL(tmp); // takes ownership
    }


// ---------------------------------------------------------------------------
// CDBMSAppUi::ApplicationDriveAndPathL()
//
// Get the application path and drive. It must be done differently in the
// development environment and in the device.
// ---------------------------------------------------------------------------
//
TFileName CDBMSAppUi::ApplicationDriveAndPathL() const
    {
    TFileName appfullname(Application()->AppFullName());
    TParse parse;

#ifdef __WINS__   // See macro definition in DBMSDb.mmp

    // On development environment the AppFullName points to z drive.
    // Replace it to point to C drive, which is writable by our application.

    parse.Set(KCDrive, &appfullname, NULL);

#else // In device use the application fullname directly.

    parse.Set(appfullname, NULL, NULL);

#endif

    TFileName fn = parse.DriveAndPath();
    // Make sure the path exists (create if not). This is needed in EMULATOR.
    BaflUtils::EnsurePathExistsL(CCoeEnv::Static()->FsSession(), fn);
    return fn;
    }

#if defined __SERIES60_3X__
// ---------------------------------------------------------------------------
// CDBMSAppUi::DatabaseDriveAndPathL()
// ---------------------------------------------------------------------------
//
TFileName CDBMSAppUi::DatabaseDriveAndPathL() const
{	
	RFs fsSession;
	User::LeaveIfError(fsSession.Connect());
	CleanupClosePushL(fsSession);
	
    TFileName appfullname, fn;
    appfullname = Application()->AppFullName();
	fsSession.PrivatePath(fn);

#ifdef __WINS__   // See macro definition in DBMS.mmp
	fn.Insert(0,KCDrive);

#else // In device use the application fullname directly.
    TParse parse;
    parse.Set(appfullname, NULL, NULL);
    fn.Insert(0,parse.Drive());   
#endif

    BaflUtils::EnsurePathExistsL(fsSession, fn);
	CleanupStack::PopAndDestroy(&fsSession);
	
    return fn;
}
#endif

// ---------------------------------------------------------------------------
// CDBMSAppUi::ShowNoteL()
//
// Show a note. Note that successive frequent calls to this method results in
// showing the latest message only.
// ---------------------------------------------------------------------------
//
void CDBMSAppUi::ShowNoteL(const TDesC& aMessage) const
    {

    CAknInformationNote* note = new(ELeave)CAknInformationNote;
    note->ExecuteLD(aMessage); // Deletes itself, when returns
    }


// ---------------------------------------------------------------------------
// CDBMSAppUi::TitlesArrayL()
//
// Build an array of Book titles from an array having Books with full info.
// ---------------------------------------------------------------------------
//
CDesCArrayFlat* CDBMSAppUi::TitlesArrayL(
    const CDesCArrayFlat* aFullDBMSInfoArray) const
    {
    // Assume the items within aFullDBMSInfoArray are in the format:
    // <Author>|<Title>|<Description>

    CDesCArrayFlat* resultArray =
        new (ELeave)CDesC16ArrayFlat(KArrayGranularity);
    CleanupStack::PushL(resultArray);

    TPtrC16 sourceRow;
    TInt startPos = 0;
    TInt endPos = 0;

    // Iterate through the DBMSs.
    // From each DBMS row, parse the <Title> and append it to result array.
    for(TInt i=0; i<aFullDBMSInfoArray->MdcaCount(); i++)
        {
        sourceRow.Set(aFullDBMSInfoArray->MdcaPoint(i));
        startPos = sourceRow.Locate('|') + 1; // exclude '|' from result
        endPos = sourceRow.LocateReverse('|');
        resultArray->AppendL(sourceRow.Mid(startPos, endPos-startPos));
        }
    CleanupStack::Pop(resultArray);
    return resultArray;
    }

// ---------------------------------------------------------------------------
// CDBMSAppUi::QueryTextL()
//
// Show simple text query dialos for the user
// ---------------------------------------------------------------------------
//
TBool CDBMSAppUi::QueryTextL(TDesC& aPrompt,
    TDes& aResultText) const
    {
   // Note: aPrompt cannot be const TDesC&, because CAknTextQueryDialog
   //       does not accept const TDesC& as a second parameter.

    CAknTextQueryDialog* dlg = new(ELeave)
        CAknTextQueryDialog( aResultText, // result is placed here
                             aPrompt,
                             CAknTextQueryDialog::ENoTone );

    dlg->SetMaxLength(aResultText.MaxLength());
    return dlg->ExecuteLD(R_SIMPLE_TEXT_QUERY);
    }

// ---------------------------------------------------------
// CDBMSAppView::HandleStatusPaneSizeChange()
// Called by framework when resource is changed.
// ---------------------------------------------------------
//
void CDBMSAppUi::HandleStatusPaneSizeChange()
	{
	CAknAppUi::HandleStatusPaneSizeChange(); //call to upper class

    if(iAppView)
    	iAppView->SetRect( ClientRect() );
    if(iListboxView)
       	iListboxView->SetRect( ClientRect() );
    if(iBookEditorView)
       	iBookEditorView->SetRect( ClientRect() );
	}
	
//EOF