Master-Child Reports Blank

rbuser

Whenever I try to create a report and creating a master-child in code the
report comes up blank if I place any child pipeline fields in a subreport.
The pipelines do contain data. And when I initially design the report the
fields
I add to the report show data in them as well. But once I preview the
report
the report is blank. And when I go back to the designer the fields are all
blank
too.

Here is the code I use to create the dataset, datasource and pipelines. It
works fine on basic pipeline reports. Even reports with multiple pipelines,
but once I try to do a master-child report (which I have added to the
method) it doesn't work.

procedure TfmDynReports.CreatePipe(PipeSQL: String; PipeID, MasterID:
Integer; MC_Mapping: String);
var
PipeQuery: TMSQuery;
PipeDataSource: TDataSource;
PipePipeline: TppDBPipeline;
m: TppMasterFieldLink;
i: Integer;
s: String;
begin
PipeQuery := TMSQuery.Create(Self);
PipeQuery.Name := Format('PipeQuery%d', [PipeID]);
PipeQuery.Connection := dmMain.dbInstitution;
PipeQuery.SQL.Text := PipeSQL;
PipeQuery.Active := True;
CreatedItems.Add(PipeQuery.Name);

PipeDataSource := TDataSource.Create(Self);
PipeDataSource.DataSet := PipeQuery;
PipeDataSource.Name := Format('PipeDataSource%d', [PipeID]);
CreatedItems.Add(PipeDataSource.Name);

PipePipeline := TppDBPipeline.Create(Self);
PipePipeline.DataSource := PipeDataSource;
PipePipeline.Name := Format('PipePipeline%d', [PipeID]);
CreatedItems.Add(PipePipeline.Name);
//setup master child if exists
{the master-child relationship is setup by doing the following
First - The master data pipeline is identified by identifying the
sql_order
value of the master pipeline. -1 in this value means there is no
master datasource
Second - The master - child field mappings are identified by the
following format: MASTER=CHILD
To add multiple master - child field mappings separate the
mappings with a semicolon like such:
MASTER=CHILD;MASTER=CHILD.
}
if MasterID <> -1 then
begin
PipePipeline.MasterDataPipeline :=
TppDBPipeline(FindComponent(Format('PipePipeline%d' , [MasterID])));
for i := 1 to ListLen(MC_Mapping, ';') do
begin
m := TppMasterFieldLink.Create(nil);
m.Name := Format('MasterFieldLink%d_%d', [PipeID, i]);
CreatedItems.Add(m.Name);
m.Parent := PipePipeline;
s := ListGetAt(MC_Mapping, i, ';');
m.MasterFieldName := ListGetAt(s, 1, '=');
m.DetailFieldName := ListGetAt(s, 2, '=');
end;
end;
end;

Bill

nardmoseley

1. Make sure that the detail query data is ordered by the linking fields (in
the exact same order).

2. I cannot determine what is happening by looking at that code. I would
approach something like this incrementally. Create a simple master detail
report at Delphi design-time - for example Customer/Orders using DBDemos.
Link the pipelines using the field links editor. Once it is working
correctly, then incrementally start converting the data access pieces to
code. First implement the pipeline creation and linking. Then run and test
until it works. Next implement the DataSource creation. Run and test. Then
implement the Query creation in code. Once all that is working, then create
the more general purpose routines. If you use DBDemos as a starting point,
then if you get stuck you can zip it up and send to
support@digital-metaphors.com and we can run it here in the debugger.

3. You can set SkipWhenNoRecords on the detail datapipeline to control
whether the master record is included in the report when no corresponding
detail data is present.