#437 Problem with Oracle LONG data types

[Piotr Brzeski]

There is a small (meybe big) problem with the long data type in oracle, displayed in TDBGRID and other similar data controls (eg VirtualDBGrid).
If the query results is more than one row, VirtualDBGrid "scrambles" the results. It looks as if it sometimes truncates TField or confuses others. The only valid TField is the last one on VirtualDBGrid. I haven't been able to work out exactly what the problem is, maybe you can do it. The way to get this problem is simple:
1. Create a table with two columns, one CLOB and one LONG.
2. Fill in the CLOB column with different values (varchar).
3. copy the CLOB column to LONG.
4. Then display the contents of all records using TVirtualDBGrid and the effect will be visible.

I am asking for a solution to the problem, or at least a hint what to do with it.

Best regards,
Piotr Brzeski

[EgonHugeist]

Hello Piotr, sorry for the delay i was in hollidays.
Could you give me a code-sniped for step 3, plz? It's uncleare how you're copying the clob to the Long field...
Which compiler do you use? Which SVN location: trunk or testing-7.3?
Note: i'm not willing using non standart components.
To get you ticket resolved quickly, just write a little test program whith a create&data-population script..
Regards, Michael

[EgonHugeist]

Ping...

[Piotr Brzeski]

Hello,
Sorry for the delay, I didn't have time to reply. The problem is with whatever GRID I use. Even with the standard TDBGrid. I can't drop the code because I reverted my ZEOS components to 7.3.0-alpha and switched IDE to CodeTyphon - the problem is no more. For a while I used the test version, the latest one available at the time. I was using the IDE Lazarus 2.0.4 with the FPC 3.0.4 compiler. Step 3:

create table test_long (
  text varchar2(4000),
  clobek clob,
  longek long
);

insert into test_long(text)
select 'ASD' from dual
union all
select 'ASDF' from dual
union all
select 'QWERT' from dual

update test_long set clobek = text

update test_long set longek = clobek

commit

select * from test_long

and after fill up to DBGrid, the more records, the bigger Mexico.

[EgonHugeist]

Honestly Oracle did deprecate the raw types, such as long, since V8. Reason is the unknown encoding and the overdozed buffer(total size is unknown) we guess to get the date fetched withoutgetting a trunkation error. However i'll check your example. And give you a reply.
Regards, Michael

[EgonHugeist]

Hello Piotr,
i was able to fix the regression with the given example.
See R6874 and a test R6875

Please test and close if OK,
Regards, Michael

[Piotr Brzeski]

Hello Michael,
Thanks for fast fix. Now it's OK.

Regards, Piotr Brzeski

[EgonHugeist]

Thank your for your confirmation, Michael