The following topics introduce the PSQL Direct Access Components for Delphi and C++ Builder:

For details on implementing this feature, see Direct Access Components Reference.

The PSQL Direct Access Components (PDAC) is a set of Visual Component Library (VCL) components that allow direct access to PSQL database engines from within the Embarcadero Delphi and C++ Builder Environments. These components offer a complete replacement for the Borland Database Engine (BDE), while providing the complete functionality of the BDE. PDAC dramatically extends the database development options available to Delphi and C++ Builder developers.

Refer to the PDAC readme file for the development environments supported by the PSQL Direct Access Components.

All versions of PDAC contain the following nonvisual components:

Supporting classes are also provided for these components.

These 32-bit components duplicate the properties, methods, and binding capabilities of the Embarcadero Data Access components, but without requiring the presence of the Borland Database Engine (BDE) at run time.

These components are provided in package format, and offer all the design time and runtime functionality of the built-in controls. They bind to the Embarcadero Data Aware controls in the same way as the BDE components, as well as to fully compatible third-party bound controls.

Special components include wwPvTable, wwPvQuery, and wwPvStoredProc and are provided for interoperability with the Woll2Woll InfoPower components.

When opening a query or table, PDAC checks for an adequate PSQL engine version to ensure that engine dependency-related errors do not occur. If the engine version is not sufficient, an exception is thrown with a message indicating the required version.

Allows SQL text to be sent directly to the engine instead of being preparsed.

This property indicates that the database contains characters encoded according to the OEM (DOS) code page, and that these characters should be converted to the ANSI (Windows) code page before use.

Please see SDK Downloads for sample code and code snippets for the PSQL Direct Access Components. You can find the online location for SDK Downloads for PDAC at the Actian PSQL website.

You install the PDAC components by unzipping the components from an archive to a directory of your choice (installdir). You must ensure that any Delphi or C++ Builder IDEs on your system can locate the components after they are unzipped.

Follow these steps to set C++ Builder project options to reflect the INCLUDE and LIBRARY paths for PDAC. These can be added to the default options, so the steps are unnecessary for every project using the PSQL components.

After the Include and Library paths are set properly, you can use the Direct Access components in exactly the same way as the corresponding Embarcadero components.

PSQL provides support for Delphi 2006 and Delphi 2007 and for C++ Builder 2007. Use the following steps to incorporate Delphi 2006, Delphi 2007, or C++ Builder 2007 into your environment.

Since Delphi 2007 and C++ Builder 2007 are binary compatible with Delphi 2006 (BDS 2006), all of your existing Embarcadero package libraries (BPLs) should work without any modification. Note that Delphi 2007 and C++ Builder 2007 declare compiler variable VERSION_180 and VERSION_185.

Follow these steps to add components to the compiler IDE for the following editions of RAD studio:

Once the components for your environment have been selected, a tab for PSQL is visible on VCL projects. Applications using PDAC can now be built by adding PvTable or PvQuery.

With a few variations regarding the Embarcadero and other runtime libraries, there are two basic ways to build PDAC applications for deployment to end users: using runtime packages or statically linking the PDAC libraries into the application's executable file. C++ Builder also offers the option of dynamically or statically linking the Embarcadero runtime library.

Using runtime packages has several advantages. It provides the smallest executable possible; this can be important where the executable or updates must be downloaded or transferred over slow links. This option allows sharing of the PDAC and Embarcadero runtime binaries and can save considerable disk space and memory in environments with many Embarcadero and PDAC applications.

A disadvantage is that more files must be distributed and kept current, and the shared files can be vulnerable to third party installations that install incorrect versions of them in shared subdirectories. If runtime packages are not used, only the application and drm.dll must be deployed. The PDAC libraries are statically linked into the executable, which will be correspondingly larger.

To use runtime packages, the developer must deploy both the application executable and the appropriate PDAC libraries (from the redist subdirectories in the PDAC installation directories), as well as any Embarcadero or other runtime libraries (borlndmm.dll, found in the compiler bin directory, is often needed) to end users.

There is a redist directory for each Embarcadero compiler. This directory contains the .bpl libraries that must be distributed with an application compiled with Build with runtime packages.

PDAC applications cannot be used with I*net Data Server (IDS). IDS is no longer a separately installable component of PSQL. Most features that were part of IDS are now integrated into the main product.

The following instructions are for building and deploying with the following versions:

In the Delphi IDE, set the appropriate options as follows:

To select packages, click Components > Install, and select the packages from the directory that matches your version of Delphi. All the packages may be selected at once.

To statically link the PDAC libraries into the application executable, clear Build with runtime packages.

If Build with runtime packages is checked at compile time, the following libraries must be installed when the application is deployed, in addition to the application itself, drm.dll, and any other packages or DLLs it requires.

From \SDK\PDAC\Delphi2006\REDIST, if their respective .dcp files are in the package build list:

These files may be installed in the same subdirectory as the application executable, but we recommend placing them in the target machine path so they may be shared by other applications. The PSQL installation \bin directory is a good choice on computers where it is the primary PSQL executable directory.

In addition, the Delphi PDAC application will require an installation of either a PSQL engine (Server or Workgroup) or a PSQL Client and a remote server appropriately installed and configured.

Starting with Delphi 6, we have changed the package naming conventions to be more compatible with Embarcadero standards. Also, the runtime packages have been separated from the design time packages in order to comply with Embarcadero requirements.

The following shows how to interpret the runtime package names if you are coming from a previous version of Delphi and PDAC: