Recreate an ADO Connection from a Template (RTM/DB)

rbuser

We have the end user reporting function working using a set of ADO
components. Name of the connection is euDatabase. Have been using as a
general purpose report builder and seems to work ok. We use .udl files to
control the ADO connections.

When exporting the report and loading in another program (or
loadfromdatabase) we have a problem with the report, when printed, not being
able to make the ADO connection - defaults to an ODBC. We have traced to
the fact that the ADO connection component in the 2nd program using the
.rtm/database record has a different name than the original program that
built the report.

This raises the question of moving reports around to different programs -
means we need to have an ability to have the calling program name the ADO
connection the same as the original and build with similar characteristics
(primarily the connection string for the .udl used). Thought maybe we could
use the information from the loaded report to recreate the connection but it
doesn't look like the report template has enough info to recreate the ADO
connection.

Is there a way to change the report, once loaded to a report component, to
use a different connection? And how can we tell what .udl is needed.

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;





--
Tech Support mailto:support@digital-metaphors.com
Digital Metaphors http://www.digital-metaphors.com

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

rbuser

Hello Nard,

Thank you very much for your high-tech tips, I combined them and created a
new method to fix the DatabaseName,
even if the report contains multiple Dataviews. Here is my solution to
resolve this issue:

procedure TfrmMain.FixDatabaseName;
var
index: integer;
aSQL: TdaSQL;
lDataModule: TdaDataModule;
lDataView: TdaDataView;
begin
//--- get a new SQL object
aSQL := TdaSQL.Create(nil);
//--- get the datamodule
lDataModule := daGetDataModule(report);
if (lDataModule <> nil) then begin
index := 0;
//--- loop through all the Dataviews
while (index < lDataModule.DataViewCount) do begin
//--- get the Dataview
lDataView := lDataModule.DataViews[index];
//--- validate the Dataview
if (lDataView <> nil) and (lDataView is TdaQueryDataView) then begin
aSQL.Assign(TdaQueryDataView(lDataView).SQL);
// ShowMessage( 'OLD DB: ' + aSQL.DatabaseName + #13#10 +
// 'NEW DB: ' + designer.DataSettings.DatabaseName );
aSQL.DatabaseName := designer.DataSettings.DatabaseName;
TdaQueryDataView(lDataView).SQL := aSQL;
end;
inc(index);
end;
end;
end;

Please let me know if I'm missing something.

Best regards,
Jorge I.

to
to
programs -
ADO
characteristics
but
ADO
to