Build a Simple VCL Application for Oracle Data

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

Create a Connection to Oracle Data

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.

To connect to Oracle, you'll first need to update your PATH variable and ensure it contains a folder location that includes the native DLLs. The native DLLs can be found in the lib folder inside the installation directory. Once you've done this, set the following to connect:

• Port: The port used to connect to the server hosting the Oracle database.
• User: The user Id provided for authentication with the Oracle database.
• Password: The password provided for authentication with the Oracle database.
• Service Name: The service name of the Oracle database.

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

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 Oracle.

Create VCL Applications with Connectivity to Oracle Data

Follow the procedure below to start executing queries to Oracle data 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 Oracle data.
   • 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 CompanyName, City FROM Customers WHERE Country = US
     

   • 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.

• DataBind Controls to Oracle Data in C++Builder
• DataBind Controls to Oracle Data in Delphi
• Viewing Oracle Data in RAD Studio Data Explorer