Tutorial updated for PostgreSQL
lazarus / 16-Databases

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BigChimp · 2012-09-14 15:19

Hi all,

I just updated the
http://wiki.lazarus.freepascal.org/SQLdb_Tutorial1
for PostgreSQL.

As always, reports on errors/omissions and possible improvements are
more than welcome.

Thanks a lot,
BigChimp

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codifies · 2012-09-15 05:39

nice tutorial!

where you say you haven't found a way to delete via a key stroke

can you not have a key up event (might have to have a key up even for
multiple components calling the same function - not sure if there is a
global key up)

procedure Tmyform.doDeleteKeyCheck(Sender: TObject; var Key: Word;
Shift: TShiftState);
begin
  if (key=KEYVAL) then
     query1.CancelUpdates;
     query1.delete;
     query1.applyUpdates;
  end;
end;

or am I missing the point!

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BigChimp · 2012-09-15 07:31

No, that looks good. Never knew about the .Delete functionality. Too
much SQL indoctrination too even consider it existed

Now I'm searching like crazy where the delete key is defined. I
vaguely remember I have to include some unit with keyboard codes but
which one???!

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codifies · 2012-09-15 08:01

sorry you will have to define the delete sql property with something
like

delete from acme where acmeid=:acmeid

it looks like you don't actually need to define the queries parameter
for the key as I assume it just uses the first one in the sql it comes
to....

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BigChimp · 2012-09-15 08:08

Actually it seems to work fine as is (the query is simple enough so
SQLDB can figure out the DELETESQL property contents).
I actually meant the VK_DELETE keycode - have opened another topic on
it:
lazarus.freepascal.org/index.php/topic,18221

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codifies · 2012-09-15 11:05

actually nix the cancelUpdates not only is it not needed it looks like
it can stop delete from working, which is odd cause I'm sure it worked
last night....

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BigChimp · 2012-09-15 17:33

Quote from: chris_c on September 15, 2012, 07:39:30 amprocedure
Tmyform.doDeleteKeyCheck(Sender: TObject; var Key: Word; Shift:
TShiftState);
begin
  if (key=KEYVAL) then
     query1.CancelUpdates;
     query1.delete;
     query1.applyUpdates;
  end;
end;

Unfortunately, for the delete key (VK_DELETE) that must be tweaked
because it currently deletes the record if you're editing a field and
e.g. trying to delete a letter by pressing the delete key.
Did this:
Code: [Select]procedure TForm1.DBGrid1KeyUp(Sender: TObject; var Key:
Word; Shift: TShiftState
  );
begin
  // Check for del key being hit and delete the current record in
response
  // as long as we're not editing data
  if (key=VK_DELETE) and (not(DBGrid1.EditorMode)) then
  begin
    //... delete current record and apply updates to db:
    SQLQuery1.Delete;
    SQLQuery1.ApplyUpdates;
  end;
end;

Suggestions for improvement welcome.

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codifies · 2012-09-15 17:51

LOL or is that DOH

I think its acceptable to inhibit the delete key removal of a record
while the focus is in an edit box...

personally I'd use alt+d via a button keyboard shortcut - accelerators
I think they used to be called...