Changing the Database settings of a template at run-time

rbuser

Using Delphi 7 and 10.06 Enterprise

Hello,

I'm loading in my report templates at runtime using the LoadFromFile
method.

When I created these templates I set the appropriate database via the
Database Settings dialog found on the "File" menu of the "Data" tab of the
main Report Builder design dialog.

Here is my problem. I have a History table in a database called Test1. I
also have another History table (identical in structure) in a database
called Test2. When I designed the template I based it on Test1. At runtime I
would like to use the same template to show the information in the Test2
database. How can I do this programmatically ? I guess I need to access the
template's Database Settings property (if there is one ?)

Ian Munro

nardmoseley

-------------------------------------------------
Tech Tip: How to modify the DatabaseName stored
with a DADE Query
-------------------------------------------------

Currently when DADE is used to create dataviews,
the DatabaseName is stored as part of the query
definition. (This is consistent with Delphi's
approach to specifying a database connection for
a Query object).

In some cases, you may decide that the
DatabaseName needs to be modified at a later date.

We recommend that the DatabaseName
refer to a TDatabase connection component or to
an Alias to provide flexibility for changing
the connection parameters.

A second way to handle this issue is to implement
some code that specifies a DatabaseName
whenever a template is loaded. This can be accomplished
by using the Report.Template.OnLoadEnd event.


1. Declare an event-handler procedure in the private
section of your form declaration.

type
myForm = class(TForm)
private
procedure ReportTemplateLoadEndEvent(Sender: TObject);
public
end;


2. Use the FormCreate event to assign the event-handler to
the event property.

procedure myForm.FormCreate(Sender: TObject)
begin
Report1.Template.OnLoadEnd := ReportTemplateLoadEndEvent;

end;

3. Add code to the event-handler to specify the database name.


procedure myForm.ReportTemplateLoadEndEvent(Sender: TObject)
var
lSQL: TdaSQL;

begin
if GetSQLObject(Report1, lSQL) then
begin
lSQL.DatabaseName := Designer.DataSettings.DatabaseName;
SetSQLObject(Report, lSQL);
lSQL.Free;

end;

end;


4. Below is a tech tip for extracting the SQL object
from a report. TdaSQL is a class defined in daSQL.pas.
The example code extracts only DataViews[0]. If the report
contains multiple dataviews, you will need to iterate thru
all of the entries in the DataViews[] array.

-------------------------------------------------
Tech Tip: How to access the SQL object associated
with a Report created using DADE
-------------------------------------------------

uses
daDatMod;


function GetSQLObject(aReport: TppReport; var aSQL: TdaSQL): Boolean;
var
lDataModule: TdaDataModule;
lDataView: TdaDataView;
begin

aSQL := TdaSQL.Create(nil);

{get the datamodule}
lDataModule := daGetDataModule(aReport);

if (lDataModule <> nil) then
begin
lDataView := lDataModule.DataViews[0];

if (lDataView <> nil) and (lDataView is TdaQueryDataView) then
aSQL.Assign(TdaQueryDataView(lDataView).SQL);

end;

Result := (aSQL <> nil);

end;


procedure SetSQLObject(aReport: TppReport; aSQL: TdaSQL);
var
lDataModule: TdaDataModule;
lDataView: TdaDataView;
begin


{get the datamodule}
lDataModule := daGetDataModule(aReport);

if (lDataModule <> nil) then
begin
lDataView := lDataModule.DataViews[0];

if (lDataView <> nil) and (lDataView is TdaQueryDataView) then
TdaQueryDataView(lDataView).SQL := aSQL;

end;

end;





--
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Digital Metaphors http://www.digital-metaphors.com

--
Nard Moseley
Digital Metaphors
www.digital-metaphors.com