How do you log a specific table in Accuracer? - delphi

Question

Code like this logs all table inserts (from the entire application):
procedure TForm1.ACRDatabase1AfterInsertRecord(Sender: TACRDataSet;
const TableName: WideString; const FieldValues: TACRArrayOfTACRVariant);
begin
if (AnsiUpperCase(TableName) = AnsiUpperCase(LogTable.TableName)) then
Exit;
if (Sender is TACRTable) then
LogTable.Insert();
LogTable.FieldByName('EventTime').AsDateTime := Now;
LogTable.FieldByName('TableName').AsString := TableName;
LogTable.FieldByName('EventType').AsString := 'Insert ';
LogTable.FieldByName('Whatever').AsString := FieldValues[4].AsString;
LogTable.Post();
end;
But fieldValues are different for each table so you might crash
the application (almost sure) using fieldvalues i.e their index number.
How do you overcome this ? Is it possible to log each table separately ?

Answer 1

As I mentioned in a comment, I don't have Accuracer, but thought it might be helpful
to post a generic method of doing client-side logging, which can capture the value
of one or more fields and be used for as many datasets as you need. You may be
able to use part of it in your ACRDatabase1AfterInsertRecord handler, as its Sender
parameter appears to identify the dataset into which the new row has been inserted.
As you can see, there is a LogFields procedure which can be included in the AfterInsert
handler of any dataset you like and this calls a separate GetFieldsToLog procedure which
adds the names of the field(s) to log for a given dataset to a temporary StringList. It's
only the GetFieldsToLog procedure which needs to be adapted to the needs of a given set of datasets.
procedure TForm1.GetFieldsToLog(ADataSet : TDataSet; FieldList : TStrings);
begin
FieldList.Clear;
if ADataSet = AdoQuery1 then begin
FieldList.Add(ADataSet.Fields[0].FieldName);
end
else
// obviously, deal with other specific tables here
end;
procedure TForm1.LogFields(ADataSet : TDataSet);
var
TL : TStringList;
i : Integer;
ValueToLog : String;
begin
TL := TStringList.Create;
try
GetFieldsToLog(ADataSet, TL);
for i := 0 to TL.Count - 1 do begin
ValueToLog := ADataSet.FieldByName(TL[i]).AsString;
// do your logging here however you want
end;
finally
TL.Free;
end;
end;
procedure TForm1.ADOQuery1AfterInsert(DataSet: TDataSet);
begin
LogFields(DataSet);
end;
Btw, one of the points of having a separate GetFieldsToLog procedure is that it helps to extend
client-side logging to changes in existing dataset records. If you generate this list
at start-up and save it somewhere, you can use it in the BeforePost event of a dataset to
pick up the current and previous values of the field (using its Value and OldValue properties),
save those in an another StringList and log them in the AfterPost event. Of course,
if you'e using a common store for these value from more than one dataset, you need to make
sure that the AfterPost of one dataset fire before the BeforePost of any other, or do the logging
entirely within the BeforePost (having to store the old and current field values between
Before- and AfterPost is messy, and it would be better to do everything in the AfterPost,
but unfortunately the OldValue is out-of-date by the time AfterPost occurs.
Be aware that getting the OldValue requires the specific dataset type to correctly implement
it. Not all types of dataset I've come across do, though, so it needs checking.
Btw #2, supposing you have a procedure like this
procedure TForm1.DoSomething(AnObject : TObject);
then you can use "if AnObject is ..." to do something like this
var
AnAdoQuery : TAdoQuery;
begin
if AnObject is TAdoQuery then begin
// First, use a cast to assign Sender to the local AnAdoQuery variable
AnAdoQuery := TAdoQuery(AnObject);
// Then, we can do whatever we like with it, e.g.
Caption := AnAdoQuery.Name;
end;
end;
Otoh, if for some reason (and I can't immediately think why we would want to but never mind)
we just want to check that what we've been passed as the AnObject parameter is a particular
object, we can omit the cast and just do
if AnObject = AdoQuery1 then
ShowMessage('Received AdoQuery1');
This equality check works, regardless of the actual class of what we've been passed
as the AnObject parameter because all other classes are descendants of AnObject's
declared class, namely TObject.