DataBind Controls to Azure Data Catalog Data in Delphi

The CData ODBC Driver for Azure Data Catalog supports the ODBC standard to enable integration of live Azure Data Catalog data with visual form designers and other rapid development tools in Delphi. The ODBC driver simplifies data access strategies for applications that share a single codebase like Delphi by providing a single API for database development. This article shows how to how to connect to Azure Data Catalog data and query data from a simple visual component library (VCL) application, as well as from Delphi code.

Create a Connection to Azure Data Catalog 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.

You can optionally set the following to read the different catalog data returned from Azure Data Catalog.

CatalogName: Set this to the CatalogName associated with your Azure Data Catalog. To get your Catalog name, navigate to your Azure Portal home page > Data Catalog > Catalog Name

Connect Using OAuth Authentication

You must use OAuth to authenticate with Azure Data Catalog. OAuth requires the authenticating user to interact with Azure Data Catalog using the browser. For more information, refer to the OAuth section in the help documentation.

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

Create VCL Applications with Connectivity to Azure Data Catalog Data

Follow the procedure below to start executing queries to Azure Data Catalog 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 Azure Data Catalog 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 DslAddressDatabase, Type FROM Tables WHERE Name = 'FactProductInventory'
   • 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.

Execute Commands to Azure Data Catalog with FireDAC Components

You can use the TFDConnection and TFQuery components to execute queries to Azure Data Catalog data. This section provides Azure Data Catalog data-specific examples of executing queries with the TFQuery component.

Connect to Azure Data Catalog Data

To connect to the data source, set the Connected property of the TFDConnection component to true. You can set the same properties from code:

Create Parameterized Queries

Parameterized resources can improve performance: 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.