Hi,
This fix
http://svn.freepascal.org/cgi-bin/viewvc.cgi/trunk/packages/fcl-db/src/base/fields.inc?r1=17199&r2=17220 fixes mising call to TField.Validate (before data are written into record buffer) and adds also call to TField.DataChanged (after data are written)

But It seems to me, that DataChanged is now called 2 times

First in TDataSet descendants in SetFieldData method (see bufdataset.pas, dbf.pas, paradox.pp, meds.pp) and second in above mentioned place.

So it would be good remove this call from TDataSet descendants. For example for bufdataset.pas:

 1860   if not (State in [dsCalcFields, dsFilter, dsNewValue]) then
 1861     DataEvent(deFieldChange, Ptrint(Field));

Laco.

Thanks. For example the code in tmsebufdataset:
"
procedure tmsebufdataset.setfielddata(field: tfield; buffer: pointer);

var
  po1: pointer;
  datasize: integer;
begin
  field.validate(buffer);
  po1:= getfieldbuffer(field,buffer = nil,datasize);
  if buffer  nil then begin
   move(buffer^,po1^,datasize);
  end
  else begin
   fillchar(po1^,datasize,0);
  end;
  fieldchanged(field);
end;
"

Martin

Hm.
No, we'll remove the call from TField.

There may be other descendants (AnyDac, Zeos and whatnot) that also call DataEvent and OnValidate, and we cannot apply this change on them.

Michael.

Michael Van Canneyt wrote / napísal(a):

Yes it seems, that we must do it in this way.
(Although I do not understand why Borland introduces this strange behavior)

Then please move approprate code at least into
TCustomBufDataset.SetFieldData
Thanks

Laco.

This code was already there.

Should the 'Validate' code be moved there too ?

Michael.

Yes. TDataset descendants are responsible to calling Validate, e.g., zeos call it inside TZAbstractRODataset.SetFieldData.

One of the reasons of letting descendants call it it's too improve granularity so Validate can be called in the middle of the routine, as is in zeos, instead to force the call before the TDataset routine.

Luiz

I agree, but I do not like idea, that SAME piece of code must be repeated in many descendants of TDataSet (TCustomBufDataSet, TParadox, TMemDataset, TFixedFormatDataSet, TDbf, TCustomSqliteDataset etc.)

So it would be good, if we can put 'validate code' into any new method? and call it once from descendants (be precise only from descendants, which are intended for use in FPC, because components which are also for Delphi must do it in Delphi compatible way and can not use this new method)

One of the reasons of letting descendants call it it's too improve granularity so Validate can be called in the middle of the routine, as is in zeos, instead to force the call before the TDataset routine.

Yes, but I think, that in many cases can be expected, that 'validate' will be called before any other action,

It seems, that TDataSet descendants never call inherited TDataSet.SetFieldData(Field: TField; Buffer: Pointer); (because it is empty method)
So if we move 'validate code' there then in 'our' descendants we put only {$IFDEF FPC}

   inherited;

{$ENDIF}
at first line. This does not affect existing tdataset descendants, and FPC dataset descendants can be adjusted to benefit from this. (I know, it is not perfect solution ;-) but I very dislike repeat same 'validate' code in X places)

--or--
introduce any new method (ValidateFieldData ? ;-))) and let tdatsset
descendants use it:
{$IFDEF FPC}
 ValidateFieldData(Field: TField; Buffer: Pointer);
{$ENDIF}

--or--
some smarter solution ?

Laco.

Ok. I will move the code.

Michael.

The whole code, which is repeated (and can be put in one place) is:

  if not (State in [dsEdit, dsInsert, dsFilter, dsCalcFields]) then
  begin
    DatabaseErrorFmt(SNotEditing,[Name],self);
    exit;
  end;
  if (Field.FieldNo>0) and not (State in [dsSetKey, dsFilter]) then
  begin
    if ReadOnly then DatabaseErrorFmt(SReadOnlyField,
[Field.DisplayName], Self);
    Field.Validate(Buffer);
  end;

Laco.

If it was just adding the call before SetFieldData it would take less than 10min, but it's necessary to know where to put so does not break something.

It's just to lines of code.

It's necessary to do some checks before calling it.

Luiz

You are right in your dislike.

I will create a 'BeforeSetFieldData' in TDataset and put the code in there, and the same for 'AfterSetFieldData' with the OnChange code.

Michael.

wrote / napísal(a):

OK,
Then please do not forget commit necessary changes also in other descendants (not only in TCustomBufDataSet but also in TParadox, TMemDataset, TFixedFormatDataSet, TDbf) to completelly fix 'missing onvalidate call' problem.
Thanks

Laco.

I am still thinking about this.
I have other solution, which is relative simple , puts base logic into base TField methods (so all TDataSet descendants can benefit from it) and does not negatively affect existing TDataSet descendants and does not require introduce new methods (BeforeSetFieldData, AfterSetFieldData). Let's distributes repeating used code as follows:

1. base checks "before" into procedure TField.SetData(Buffer: Pointer;
NativeFormat : Boolean);
  820 begin
  821   If Not Assigned(FDataset) then
  822     DatabaseErrorFmt(SNoDataset,[FieldName]);
        if not (State in [dsEdit, dsInsert, dsFilter, dsCalcFields]) then //here should be IMO also dsNewValue
          DatabaseErrorFmt(SNotEditing,[FDataSet.Name],FDataSet);
        if ReadOnly and (FieldNo>0) and not (FDataSet.State in [dsSetKey, dsFilter]) then
          DatabaseErrorFmt(SReadOnlyField, [DisplayName], Self);
  829   FDataSet.SetFieldData(Self,Buffer, NativeFormat);
--------------------------------------------------------------------------
2. into procedure TField.Validate(Buffer: Pointer);
  892 begin
        if FDataSet.State in [dsSetKey, dsFilter] then Exit;
  893   If assigned(OnValidate) Then

--------------------------------------------------------------------------

3. "after call" into procedure TDataSet.SetFieldData(Field: TField; Buffer: Pointer);
     begin
       if not (State in [dsCalcFields, dsFilter, dsNewValue]) then
         DataEvent(deFieldChange, Ptrint(Field));
     end;

--------------------------------------------------------------------------

And now all what we must do, is put into method SetFieldData in TDataSet descendants one line:

Field.Validate(Buffer);

and one line at end:

inherited; //calls "field change" ... this is done by all TDataSet descendants in fcl-db as a last thing

It is only draft, so some detils may be changed ... ;-) What do you think ?

Laco.

I still think that is overkill: adding a method to replace just two lines of code.

Anyway, if you decide this way, consider another name. Sometimes is to be called in the "middle" of SetFieldData

and the same for 'AfterSetFieldData' with the OnChange code.

This one is a bit more odd since currently only bufdataset will use it (or do you plan to replace the existing code in descendants?)

Luiz

Small optimalization use dsWriteModes instead of fixed set:

- if not (State in [dsEdit, dsInsert, dsFilter, dsCalcFields]) then //here should be IMO also dsNewValue

+ if not (FDataSet.State in dsWriteModes) then

Laco.

Hi,
here are diffs with changes, I hope they will be good for all TDataSet descendants (those specific to FPC and also those which are also for use in Delphi)
Code which is general (and is used repeatedly) is placed in TField methods and only small code remains which must be placed into each TDataSet descendant.
(I patched only TBufDataSet, but later can be updated also other TDataSet descendants ... remove redundant code and add Field.Validate(...)) Thanks
-Laco.

Michael,
do you plan do something else with this "OnValidate" problem ? Thanks
-Laco.

LacaK wrote

Michael, do you plan do something else with this "OnValidate" problem ?

I thought I had done everything, or did I (again) forget something ?

Michael.

>/ Michael,

/>>/ do you plan do something else with this "OnValidate" problem ? /

I thought I had done everything, or did I (again) forget something ?

There is IMHO unresolved original problem which is in fact, that some TDataSet descendants implement call to Field.Validate in descendant's SetFieldData (for example ZEOS in procedure TZAbstractRODataset.SetFieldData)

So if we leave call to Validate(Buffer) in TField.SetData ( http://svn.freepascal.org/cgi-bin/viewvc.cgi/trunk/packages/fcl-db/src/base/fields.inc?r1=17199&r2=17220 )

Then in case of these TDataSet descendants will Validate called twice. (once in TField.SetData and second in descendant's SetFieldData)

Please look at diff's which are attached in my email from 13.4.2011. (There are changes which we must/can do to fix it)

Thanks
-Laco.