Build a Simple VCL Application for Presto データ

How to build a simple VCL Application to view Presto データ in RAD Studio using the CData ODBC Driver for Presto.

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 Presto, you gain access to live Presto データ within RAD Studio, abstracting the data into tables, views, and stored procedures that can be used to retrieve and update Presto データ. This article will walk through connecting to Presto and creating a simple VCL application with the Form Designer.

Create a Connection to Presto 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.

Presto への接続には、まずはServer およびPort を接続プロパティとして設定します。それ以外の追加項目は接続方式によって異なります。

TLS/SSL を有効化するには、UseSSL をTRUE に設定します。

LDAP で認証

LDAP で認証するには、次の接続プロパティを設定します:

  • AuthScheme: LDAP に設定。
  • User: LDAP で接続するユーザー名。
  • Password: LDAP で接続するユーザーのパスワード。

Kerberos 認証

KERBEROS 認証を使う場合には、以下を設定します:

  • AuthScheme: KERBEROS に設定。
  • KerberosKDC: 接続するユーザーのKerberos Key Distribution Center (KDC) サービス。
  • KerberosRealm: 接続するユーザーのKerberos Realm 。
  • KerberosSPN: Kerberos Domain Controller のService Principal Name。
  • KerberosKeytabFile: Kerberos principals とencrypted keys を含むKeytab file。
  • User: Kerberos のユーザー。
  • Password: Kerberos で認証するユーザーのパスワード。

You can then follow the steps below to use the Data Explorer to create a FireDAC connection to Presto データ.

  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 Presto.

Create VCL Applications with Connectivity to Presto データ

Follow the procedure below to start executing queries to Presto データ 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 Presto データ.
    • 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 FirstName, LastName FROM Customer WHERE Id = '123456789'
    • 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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