TECH TIP: Controlling the End-User Environment

If you are having difficulty getting the Data tab, the Calc tab, the crosstab component or the TeeChart component to appear in your end-user application, or you are trying to eliminate one of these capabilities from the app, then this help topic is for you.  The following paragraphs explain the unit registration scheme used by ReportBuilder Pro, and how you can use this scheme to get control over the feature set presented to your end-users.

In order to minimize the overhead in end-user reporting applications, ReportBuilder employs a unit level registration scheme (similar to component registration in Delphi.), whereby components and functionality can be added at the discretion of the developer. In other words, you can control whether the ‘Data’ workspace, the ‘Calc’ workspace or certain components appear in your end-user reporting application simply by specifying or omitting certain unit names from the uses clause of your main end-user reporting unit. The advantage of this approach is that overhead associated with features such as DADE, RAP or the crosstab component can be eliminated from your application if you do not wish to pass these features along to the end-user.  The disadvantage is that you must manually add certain units to the uses clause or these capabilities will not appear in the application.

In the end-user reporting demo project (located in the …\RBuilder\Demos\1. Report Explorer directory), the main unit is a form entitled myEURpt.  At the top of the unit for this form there is a series of conditional compiler directives which, when enabled, cause certain functionality to appear in the application.  The conditional compiler directives in this unit are an attempt to simplify the configuration of the demo application.  However, these directives do nothing more than add or omit certain unit names from the uses clause of the form.  The important thing to know is the unit names and the functionality that including those unit names will provide.  The table below provides this information.

ReportBuilder also uses the unit registration scheme to control which database connectivity options are provided by the application.  While including the daDatMan unit will cause the ‘Data’ workspace to appear in the Report Designer, that workspace will not be functional without a supporting implementation.  In ReportBuilder we call these implementations DADE plug-ins.  A DADE plug-in is nothing more than a Delphi unit which contains the appropriate descendant class implementations needed by DADE to communicate with a given database.  Placing the data access implementation in a separate unit gives us at least two benefits.  One is that the user interface is not tied to any specific database connectivity scheme.  The other is that the overhead associated with database support is limited to the database connectivity products you are actually using.  This means that if you are using ADO to access your data, you need only include the daADO unit in your uses clause and your application will use ADO only. Most developers use DADE plug-ins to gain access to databases not supported by the BDE, or to gain access to databases without the use of the BDE.  The following DADE plug-ins are provided with ReportBuilder Pro:

You can use DADE plug-ins at Delphi design-time by generating a package which contains one of these units and then installing it into Delphi. This will allow you to use your preferred database product within the ‘Data’ workspace at Delphi design-time.  You can locate the various DADE plug-in units in the …\RBuilder\ Demos\EndUser Databases directories.  A Delphi package project has been provided for each DADE implementation so that you can generate and install the plug-in at Delphi design-time. For more information on how this can be done, see the ReadMe files in the EndUser Databases directories.

Additional DADE Plug-ins are always being developed.  Check the Digital Metaphors web-site for the latest information (see the section Download:DADE Plug-Ins.)