Hi *,
I have 2 questions, which I divide into 2 emails.

1st is about TField.OldValue and Delphi compatibility. Please look at small attached program (for SQLite3).

In Delphi (with TClientDataSet and dbExpress) outputs:
1. Field.OnValidate: OldValue=N; Value=N; NewValue=N
2. Field.OnChange: OldValue=O; Value=N; NewValue=N
3. BeforePost: OldValue=O; Value=N; NewValue=N
4. AfterPost: OldValue=O; Value=N; NewValue=N
5. Before ApplyUpdates: OldValue=O; Value=N; NewValue=N
6. After ApplyUpdates: OldValue=N; Value=N; NewValue=N

In FPC:
1. Field.OnValidate: OldValue=N; Value=N; NewValue=N
2. Field.OnChange: OldValue=null; Value=N; NewValue=N
3. BeforePost: OldValue=null; Value=N; NewValue=N
4. AfterPost: OldValue=O; Value=N; NewValue=N
5. Before ApplyUpdates: OldValue=O; Value=N; NewValue=N
6. After ApplyUpdates: OldValue=null; Value=N; NewValue=N

As you can see, there are differences in 2,3,6, where in FPC OldValue is NULL but in Delphi is it "old value".
Dou you think, that it is bug ? (at least it makes impossible compare OldValue and Value in BeforePost event handler and take some action when some field changes)

TIA
L.

At least it is a bug in 2,3.
The OldValue should IMHO be available till the Post statement. After that, it is subject to debate.

Michael.

Ladislav Karrach wrote

Thanks, I reported it in bug tracker http://bugs.freepascal.org/view.php?id=19542

Well, Joost is going to have a field day with those...

Michael.