Author: Tim...

Yesterday I sounded like Barry White, today I can’t speak, much to the delight of my co-workers. I feel fine, but when I talk nothing comes out. Perhaps I should write all this text with a white font on a white background to simulate my current situation.

This reminds me of a summer holiday during University, when I worked on a production line in a factory for 3 months. All but one of the guys I worked with were deaf, and the one guy that could hear was at the other end of the line so I never got to speak to him. Fortunately the guys were really good at lip reading, so for 3 months I talked at work mostly without making any sound. I remember having a “chat” in the canteen one lunchtime and I started to speak out loud and got some funny looks from some of the guys off another line. It was only then I realized they had assumed I was deaf to as they had never heard me speak out loud 🙂

I had to teach a class last night using the “do as I do” method. Thought I would save my voice. Fat lot of good that did me!

I’ve just noticed that a Developers Release of Oracle Database 10g Release 2 (10.2.0.1.0) for Microsoft Windows is available for download. Not sure what’s missing from this, but it’s not a fully supported production release like the Linux version.

Cheers

Tim…

I’ve said it before and I’ll say it again, Oracle products don’t run properly on Tru64 anymore!

The latest issue came from an observation by a developer and involves problems with using NVL inside an EXISTS subquery. The following code is the test case I sent in my TAR to Oracle support.

CREATE TABLE tab1 (
code         VARCHAR2(10),
description  VARCHAR2(50)
);

ALTER TABLE tab1 ADD (
CONSTRAINT tab1_pk PRIMARY KEY (code)
);

INSERT INTO tab1 (code, description) VALUES ('1', 'ONE');
INSERT INTO tab1 (code, description) VALUES ('2', 'TWO');
INSERT INTO tab1 (code, description) VALUES ('3', 'THREE');

CREATE TABLE tab2 (
code         VARCHAR2(10),
tab1_code    VARCHAR2(10),
description  VARCHAR2(50)
);

ALTER TABLE tab2 ADD (
CONSTRAINT tab2_pk PRIMARY KEY (code)
);

ALTER TABLE tab2 ADD (
CONSTRAINT tab2_tab1_fk FOREIGN KEY (tab1_code)
REFERENCES tab1(code)
);

CREATE INDEX tab2_tab1_fk_i ON tab2(tab1_code);

INSERT INTO tab2 (code, tab1_code, description) VALUES ('1', '1', 'ONE');
INSERT INTO tab2 (code, tab1_code, description) VALUES ('2', '1', 'ONE');
INSERT INTO tab2 (code, tab1_code, description) VALUES ('3', '1', 'ONE');
INSERT INTO tab2 (code, tab1_code, description) VALUES ('4', '2', 'TWO');
INSERT INTO tab2 (code, tab1_code, description) VALUES ('5', '2', 'TWO');
INSERT INTO tab2 (code, tab1_code, description) VALUES ('6', '2', 'TWO');
INSERT INTO tab2 (code, tab1_code, description) VALUES ('7', '3', 'THREE');
INSERT INTO tab2 (code, tab1_code, description) VALUES ('8', '3', 'THREE');
INSERT INTO tab2 (code, tab1_code, description) VALUES ('9', '3', 'THREE');

COMMIT;

VARIABLE p1 VARCHAR2(1)
BEGIN
:p1 := '%';
END;
/

SELECT t1.code
FROM   tab1 t1
WHERE  EXISTS(SELECT rowid
FROM   tab2 t2
WHERE  t2.tab1_code = t1.code
AND    t2.code like :p1)
ORDER BY t1.code;

CODE
----------
1
2
3

3 rows selected.

SELECT t1.code
FROM   tab1 t1
WHERE  EXISTS(SELECT rowid
FROM   tab2 t2
WHERE  t2.tab1_code = t1.code
AND    t2.code like NVL(:p1,'%'))
ORDER BY t1.code;

CODE
----------
1
1
1
2
2
2
3
3
3

9 rows selected.

SELECT t1.code
FROM   tab1 t1
WHERE  EXISTS(SELECT rowid
FROM   tab2 t2
WHERE  t2.tab1_code = t1.code
AND    t2.code like COALESCE(:p1,'%'))
ORDER BY t1.code;

CODE
----------
1
2
3

3 rows selected.

From this you can see that then the bind variable is set to ‘%’ the query without the NVL works as expected, but the query using the NVL displays a row in the master table for each row found in the subquery. In comparison, the query using the COALESCE function works fine.

Now I realise that this is not a great query anyway, but you would still expect it to work!

Happy days in Tru64 land again 🙂

Once again I’m drawn to the inevitable conclusion that running Oracle products on anything but a tier-one platform is a bad idea. What’s more, judging by the recent arrival of Oracle 10g Release 2, there is now only a single tier-one platform. I don’t see a version for Solaris, HP-UX or Windows yet.

As for me, I’m still waiting for 10.1.0.4.0 to be released on Tru64. Release 2 is a long way off 🙂

Cheers

Tim…