Dataviews

rbuser

We have some reports that use custom dataviews for report writer
versions 5.56 and 5.52. I do not want to use them anymore and
wondered if there was some way to switch the dataviews at run-time
(for customers custom reports for example) and convert them to use new
datamodules that I write using dbpipeline fields.

digitalmetaphors

Let me get this traight, you want to take the dataviews that your customer
has created, and convert them to be delphi data access components on your
datamodule?

Do you have something coded to handle autosearch criteria that your users
may have created in the dataviews? The rest of it is pretty easy, except
order by's maybe. If you have indexes and are using table components it may
not be a problem.

Master detail links may be a problem too, as you will have to parameterize a
query, or tell the dataviews to generate the magic SQL and the copy the
magic SQL to queries on yoru datamodule.

You'll have to loop through the dataview in the report and extract their SQL
objects. I'm sure you've seen this posted before, but this example
(updated yesterday) show how to do this:
http://www.digital-metaphors.com/tips/ExtractSQLObject.zip

Check the SQL object's EditSQLAsText property as the first step, as you can
simple copy the SQLText to a query on a form. If it is false, then you'll
have to loop through the select fields, order by fields, calc fields, group
fields, and serach criteria fields to build queries. If there is MD linking,
then I think you'll want to load the user's template, open the pipelines
which the report is using (which will cause the dataviews to generate the
magic SQL) and then read the magic SQL from the SQL objects and copy it into
your queries. Then you'll have to create the master field links on the
pipelines as well. See the article below.


Cheers,

Jim Bennett
Digital Metaphors

---------------------------------------------------------
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.


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