Post in master calls AfterPost in detail
lazarus / 16-Databases

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fpcoder · 2017-03-13 10:26

qryDetail has qryMaster as DataSource.

Is it expected behaviour that qryMaster.Post triggers AfterPost in
qryDetail?

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Thaddy · 2017-03-13 10:35

Why would you expect otherwise? You may have to update the detail to
reflect the current status.

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fpcoder · 2017-03-13 11:22

Still learning about database events. Why is qryDetail.AfterPost
triggered by qryMaster?

I have a settings dialog where fields in qryMaster are edited and
posted first, and if qryDetail is modified too it is also posted. But
it never gets posted since qryMaster triggered qryDetail's afterpost
and qryDetail.Modified is no longer true:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i function
TfrmDataset.SaveDataset: Boolean;begin  Result:=False;  if
ValidateInput then  try    try      DM.qryDataset.Post;     
DM.qryDataset.ApplyUpdates;       if DM.qryLinks.Modified then     
begin        DM.qryLinks.FieldByName('dataset_id').AsInteger:=       
DM.qryDataset.FieldByName('dataset_id').AsInteger;        
DM.qryLinks.Post;        DM.qryLinks.ApplyUpdates;      end;     
DM.TX.CommitRetaining;      Result:=True;    except     
DM.TX.RollbackRetaining;    end;  finally    DM.qryLinks.Close;   
DM.qryDataset.Close;  end;end;
I supply the dataset_id manually since UpdateSQL/InsertSQL etc doesn't
make use of parameters.

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goodname · 2017-03-13 17:09

Not really what you were asking but try not to use the CommitRetaining
or RollbackRetaining in transactions. It leads to long running idle
transactions which is generally considered to be a program bug.
Instead use TSQLQuery option sqlAutoCommit or sqlKeepOpenOnCommit with
Commit.

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fpcoder · 2017-03-15 19:19

@goodname Good to know, I changed to sqlKeepOpenOnCommit and it seems
to work fine.

When it was clear that Post of detail is triggered by Post of master,
I assigned the dataset_id value in detail's BeforePost and called
ApplyUpdates in detail's AfterPost.