[fpc-devel] About TDataSet master/detail design in fpc
Michael Van Canneyt
michael.vancanneyt at wisa.be
Fri May 6 17:10:03 CEST 2005
On Fri, 6 May 2005, Luiz Américo wrote:
> I noticed that in the current cvs of fpc it's implemented the master/detail
> relation between TDataset(s).
> I saw that TDetailDataLink and TMasterDataLink was introduced but I couldn't
> figure how is supposed to work. I also noticed the abscense of NestedDatasets
> and DataSetField properties.
They are not yet implemented. But NestedDataset and DatasetField are
ONLY for TClientDataset, and we don't support TClientDataset (yet).
> I'd be glad if someone could explain how the design works and what is
> expected from a TDataset descendant that support it.
Nothing is expected, i.e. TDataset does not implement anything
concerning master/detail. How could it ?
> I'll try to implement it in TSqliteDataSet.
What you must do is
1. Implement parameter support (TParams/TParam is present).
2. Introduce a Datasource property. Whenever the Datasource changes it's
data, the detail dataset most close, fill in new parameters, and
2 is not a problem, this is max 50 lines of code. 1 is the problem.
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