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DataBind Controls to FTP Data in Delphi


DataBind to FTP data in Delphi with standard data access components and controls.

The CData ODBC driver for FTP supports the ODBC standard to enable integration of live FTP 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 FTP data and query data from a simple visual component library (VCL) application, as well as from Delphi code.

Create a Connection to FTP 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 FTP or SFTP servers, specify at least RemoteHost and FileProtocol. Specify the port with RemotePort.

Set User and Password to perform Basic authentication. Set SSHAuthMode to use SSH authentication. See the Getting Started section of the data provider help documentation for more information on authenticating via SSH.

Set SSLMode and SSLServerCert to secure connections with SSL.

The data provider lists the tables based on the available folders in your FTP server. Set the following connection properties to control the relational view of the file system:

  • RemotePath: Set this to the current working directory.
  • TableDepth: Set this to control the depth of folders to list as views.
  • FileRetrievalDepth: Set this to retrieve and list files recursively from the root table.

Stored Procedures are available to download files, upload files, and send protocol commands. See the Data Model chapter of the FTP data provider documentation for more information.

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

Create VCL Applications with Connectivity to FTP Data

Follow the procedure below to start executing queries to FTP 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 FTP 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 Filesize, Filename FROM MyDirectory
    • 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 FTP with FireDAC Components

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

Connect to FTP 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:

FDConnection1.ConnectionDefName := 'myftp'; FDConnection1.Connected := true;

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.

FDQuery1.Open('select * from MyDirectory where FilePath = :FilePath',['/documents/doc.txt']);

To execute a query that does not return a result set, such as a delete, 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.

FDQuery1.ExecSQL('delete from MyDirectory where Id= :myId',['x12345']); 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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The FTP ODBC Driver is a powerful tool that allows you to connect with live data from remote files and directories, directly from any applications that support ODBC connectivity.

Access remote data like you would a database through a standard ODBC Driver interface.

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