How can i assign TppDBPipeline MasterFieldLinks by code?

rbuser

Hi,

How can i assign ADetailPipeline (TppDBPipeline) MasterFieldLinks (Joined
fields between master and detail) by code?

Greetings,
Filip Moons

nicocizik

Hi Filip,

---------------------------------------------------------
Tech Tip: Define Master/Detail DataPipeline Links in Code
---------------------------------------------------------

Defining a Master/Detail relationship for a DataPipeline
requires that the detail pipeline have the
following properties defined:

1. MasterDataPipeline

2. MasterFieldLinks


At Delphi design-time you can use the object inspector
and the DataPipeline's FieldLinks editor to define
the master/detail relationship.


The following example illustrates how to define the
master/detail relationship dynamically at run-time.


var
lFieldLink: TppMasterFieldLink;


begin

{define the master/detail pipeline relationship}
plDetail.MasterDataPipeline := plMaster;

{create a new field link }
lFieldLink := TppMasterFieldLink.Create(nil);

lFieldLink.Parent := plDetail;

{assign the detail field name}
lFieldLink.DetailFieldName := 'CustNo';

{assign the master field name}
lFieldLink.MasterFieldName := 'CustNo';


end;


Note: The DataPipeline linking requires the records in the detail dataset to
be ordered by the linking fields. In the above example, the detail data must
be ordered by CustNo.



--
Regards,

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

rbuser

Hi Nico,

-How do I delete/clear existing Master/Detail DataPipeline Links at Runtime?
-Do I have to free the Master/Detail DataPipeline Links when i'm done using
them or will they be freed automatically by setting the 'FieldLink.Parent'?

Greetings and thx for your always swift response,
Filip

nicocizik

Hi Filip,

1. You can either just re-assign the links if you need to change them, or
assign them to nil to clear them out.

2. Yes, you will need to free the FieldLink.

--
Regards,

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

rbuser

Hi Nico,

Sorry for bothering u again, but i'm still a bit unclear bout the clearing
and freeing the MasterFieldLinks.
I have 4 pipelines whichs MasterFieldLinks need to setup at runtime
depending on what sorting the user wants. Each pipeline needs to get several
MasterFieldLinks added, again depending on what sorting the user wants. How
do i delete and free MasterFieldLinks when printing is done? Could u please
give me a example, i don't find anything bout TppMasterFieldLink in the
online help. Do i iterate the forms componentcount and freeandnil all
TppMasterFieldLink class objects from the form?

Thx,
Filip Moons

procedure TLEX33100F.BuildMasterFieldLinks;

procedure AddFieldLink(APipeLine: TppDBPipeline;
AMasterFieldName,ADetailFieldName: string);
var
AFieldLink: TppMasterFieldLink;
begin
// Create a new FieldLink
AFieldLink := TppMasterFieldLink.Create(nil);
// Assign the FieldLink Parent
AFieldLink.Parent := APipeLine;
// Assign the FieldLink MasterFieldName
AFieldLink.MasterFieldName := AMasterFieldName;
// Assign the FieldLink DetailFieldName
AFieldLink.DetailFieldName := ADetailFieldName;
end; {AddFieldLink}

begin
// Toewijzen MasterFieldLinks Dagboek
if cbTotDGB.ItemIndex = 0 then
begin
AddFieldLink(ppLYACT_TOT_DGB,'LYDCDGB','LYDCDGB');
if cbTotJR.ItemIndex = 0 then
AddFieldLink(ppLYACT_TOT_JR,'LYDCDGB','LYDCDGB');
if cbTotKW.ItemIndex = 0 then
AddFieldLink(ppLYACT_TOT_KW,'LYDCDGB','LYDCDGB');
if cbTotMND.ItemIndex = 0 then
AddFieldLink(ppLYACT_TOT_MND,'LYDCDGB','LYDCDGB');
end;

// Toewijzen MasterFieldLinks Jaar
if cbTotJR.ItemIndex = 0 then
begin
AddFieldLink(ppLYACT_TOT_JR,'LYDCYEAR','LYDCYEAR');
if cbTotKW.ItemIndex = 0 then
AddFieldLink(ppLYACT_TOT_KW,'LYDCYEAR','LYDCYEAR');
if cbTotMND.ItemIndex = 0 then
AddFieldLink(ppLYACT_TOT_MND,'LYDCYEAR','LYDCYEAR');
if cbTotDGB.ItemIndex <> 0 then
AddFieldLink(ppLYACT_TOT_DGB,'LYDCYEAR','LYDCYEAR');
end;

// Toewijzen MasterFieldLinks Kwartaal
if cbTotKW.ItemIndex = 0 then
begin
AddFieldLink(ppLYACT_TOT_KW,'LYDCKWART','LYDCKWART');
if cbTotMND.ItemIndex = 0 then
AddFieldLink(ppLYACT_TOT_MND,'LYDCKWART','LYDCKWART');
if cbTotDGB.ItemIndex <> 0 then
AddFieldLink(ppLYACT_TOT_DGB,'LYDCKWART','LYDCKWART');
end;

// Toewijzen MasterFieldLinks Maand
if cbTotKW.ItemIndex = 0 then
begin
AddFieldLink(ppLYACT_TOT_MND,'LYDCMONTH','LYDCMONTH');
if cbTotDGB.ItemIndex <> 0 then
AddFieldLink(ppLYACT_TOT_DGB,'LYDCMONTH','LYDCMONTH');
end;

// Toewijzen MasterFieldLinks Dagboek
if cbTotDGB.ItemIndex <> 0 then
AddFieldLink(ppLYACT_TOT_DGB,'LYDCDGB','LYDCDGB');
end; {BuildMasterFieldLinks}

nicocizik

Hi Filip,

You will need to keep track of all the field links you create and free them
accordingly as you need to clear them. ReportBuilder creates a TList
component to hold all the links that are created and then iterates through
the list to free each link when they need to be destroyed.

--
Regards,

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