Build a Simple VCL Application for OData Services

How to build a simple VCL Application to view OData services in RAD Studio using the CData ODBC Driver for OData.

最終更新日:2023-06-12

Embarcadero RAD Studio provides a development environment for Delphi and C++Builder applications. With the CData ODBC Driver for OData, you gain access to live OData services within RAD Studio, abstracting the data into tables, views, and stored procedures that can be used to retrieve and update OData services. This article will walk through connecting to OData and creating a simple VCL application with the Form Designer.

Create a Connection to OData Services

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.

OData への接続

OData に接続するには、Url を有効なOData サービスルートURI に設定する必要があります。 OData サービスにルートドキュメントがない場合、テーブルとして公開したい特定のエンティティをFeedURL に指定してください。

OData への認証

OData は、以下を経由する認証をサポートします。

  • HTTP
  • Kerberos
  • SharePoint Online
  • OAuth
  • Azure AD

HTTP 認証スキーム

HTTP で認証する場合は、次の表に従ってAuthScheme を設定します。

SchemeAuthSchemeその他の設定
NoneNone認証を必要としない場合に使用。
BasicBasicUserPassword
NTLMNTLMUserPassword
Digest(サポートされている場合)DigestUserPassword

その他の認証方法の詳細は、ヘルプドキュメントの「接続の確立」セクションを参照してください。

You can then follow the steps below to use the Data Explorer to create a FireDAC connection to OData services.

  1. In a new VCL Forms application, expand the FireDAC node in the Data Explorer.
  2. Right-click the ODBC Data Source node in the Data Explorer.
  3. Click Add New Connection.
  4. Enter a name for the connection.
  5. In the FireDAC Connection Editor that appears, set the DataSource property to the name of the ODBC DSN for OData.

Create VCL Applications with Connectivity to OData Services

Follow the procedure below to start executing queries to OData services from a simple VCL application that displays the results of a query in a grid.

  1. Drop a TFDConnection component onto the form and set the following properties:

    • ConnectionDefName: Select the FireDAC connection to OData services.
    • Connected: Select True from the menu and, in the dialog that appears, enter your credentials.
  2. 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 Orders.Freight, Customers.ContactName FROM Customers INNER JOIN Orders ON Customers.CustomerId=Orders.CustomerId
    • Active: Set this property to true.
  3. 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.
  4. Drop a TDBGrid control onto the form and set the following property:

    • DataSource: Select the name of the TDataSource.
  5. Drop a TFDGUIxWaitCursor onto the form — this is required to avoid a run-time error.

You now have an executable application that displays the results of the SQL Query set in the TFDQuery object.

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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