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DataBind Controls to Dropbox データ in C++Builder
DataBind to Dropbox のデータ in C++Builder with standard components and controls.
最終更新日：2023-06-12The CData ODBC Driver for Dropbox makes it easy to integrate connectivity to live Dropbox のデータ with standard data access components in C++Builder. This article shows how to create a simple visual component library (VCL) application in C++Builder that connects to Dropbox のデータ, executes queries, and displays the results in a grid. An additional section shows how to use FireDAC components to execute commands from code.
Create a Connection to Dropbox データ
If you have not already, first specify connection properties in an ODBC DSN (data source name). This is the last step of the driver installation. You can use the Microsoft ODBC Data Source Administrator to create and configure ODBC DSNs.
OAuth では認証するユーザーにブラウザでDropbox との通信を要求します。CData 製品は、以下のようにさまざまな方法でこれを容易にします。 ユーザー資格情報の接続プロパティを設定せずに接続できます。 接続すると、CData 製品はデフォルトブラウザでOAuth エンドポイントを開きます。ログインして、CData 製品にアクセス許可を与えます。CData 製品がOAuth プロセスを完了します。
他のOAuth 認証フローについては、ヘルプドキュメントの「OAuth 認証の使用」を参照してください。
なお、Dropbox Driver はDropbox のファイルの一覧表示やユーザー管理情報の取得用です。Dropbox に保管されているExcel、CSV、JSON などのファイル内のデータを読み込みたい場合には、Excel Driver、CSV Driver、JSON Driver をご利用ください。
You can then follow the steps below to use the Data Explorer to create a FireDAC connection to Dropbox.
- In a new VCL Forms application, expand the FireDAC node in the Data Explorer.
- Right-click the ODBC Data Source node in the Data Explorer.
- Click Add New Connection.
- Enter a name for the connection.
- In the FireDAC Connection Editor that appears, set the DataSource property to the name of the ODBC DSN for Dropbox.
Create VCL Applications with Connectivity to Dropbox データ
Follow the procedure below to start querying Dropbox のデータ from a simple VCL application that displays the results of a query in a grid.
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Drop a TFDConnection component onto the form and set the following properties:
- ConnectionDefName: Select the FireDAC connection to Dropbox.
- Connected: Select True from the menu and, in the dialog that appears, enter your credentials.
-
Drop a TFDQuery component onto the form and set the properties below:
- Connection: Set this property to the TFDConnection component, if this component is not already specified.
SQL: Click the button in the SQL property and enter a query. For example:
SELECT Id, Name FROM Files- Active: Set this property to true.
Drop a TDataSource component onto the form and set the following property:
- DataSet: In the menu for this property, select the name of the TFDQuery component.
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Drop a TDBGrid control onto the form and set the following property:
- DataSource: Select the name of the TDataSource.
- Drop a TFDGUIxWaitCursor onto the form — this is required to avoid a run-time error.
Execute Commands to Dropbox with FireDAC Components
You can use the TFDConnection and TFQuery components to execute queries to Dropbox のデータ. This section provides dropboxspecific examples of executing queries with the TFQuery component.
Connect to Dropbox データ
To connect to the data source, set the Connected property of the TFDConnection component to true. You can set the same properties from code:
FDConnection1->ConnectionDefName = "CData Dropbox ODBC Source";
FDConnection1->Connected = true;
To connect the TFDQuery component to Dropbox のデータ, set the Connection property of the component. When a TFDQuery component is added at design time, its Connection property is automatically set to point to a TFDConnection on the form, as in the application above.
Create Parameterized Queries
To create a parameterized query, use the following syntax below:
FDQuery1->SQL->Text = "select * from Files where id = :Id";
FDQuery1->ParamByName("id")->AsString = "1";
query->Open();
The example above binds a string-type input parameter by name and then opens the dataset that results.
Prepare the Statement
Preparing statements is costly in system resources and time. The connection must be active and open while a statement is prepared. By default, FireDAC prepares the query to avoid recompiling the same query over and over. To disable statement preparation, set ResourceOptions.DirectExecute to True; for example, when you need to execute a query only once.
Execute a Query
To execute a query that returns a result set, such as a select query, use the Open method. The Open method executes the query, returns the result set, and opens it. The Open method will return an error if the query does not produce a result set.
FDQuery1->SQL->Text := "select * from Files where id = :Id";
FDQuery1.ParamByName("id")->AsString = "1";
FDQuery1->Open();
To execute a query that does not return a result set, use the ExecSQL method. The ExecSQL method will return an error if the query returns a result set. To retrieve the count of affected rows use the TFD.RowsAffected property.
FDQ.SQL.Text := "delete from Files where Id = :Id";
FDQuery1->Params->Items[0]->AsString = "x12345";
FDQuery1->ExecSQL();
AnsiString i = FDQuery1->RowsAffected;
Related Articles
Below you can find other articles for using the CData ODBC Driver with RAD Studio, Delphi, and C++ Builder.
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