I'm currently using Postgre 8.2. Are there something wrong with that
version?
Below is the DDL for my table:
CREATE TABLE absensi (
id_absensi integer NOT NULL,
id_user integer,
tanggal date,
keterangan character varying,
id_tipe_absensi integer
);
ALTER TABLE ONLY absensi
ADD CONSTRAINT absensi_pkey PRIMARY KEY (id_absensi);
ALTER TABLE ONLY absensi
ADD CONSTRAINT unique_absen UNIQUE (id_user, tanggal);
below are examples of instance of two records:
R1: 1001, 1, 02-25-2008, Present, 1
R2: 1001, 1, 02-25-2008, Present, 1
The two records are identical. But if i display the ctid, the two
records differ as they
have different ctid (suppose i display the ctid in the first column):
R1: 8888, 1001, 1, 02-25-2008, Present, 1
R2: 9999, 1001, 1, 02-25-2008, Present, 1
Many thanks for your help.
Nizar
=====
Alban Hertroys wrote:
On Mar 7, 2008, at 9:28 AM, Achmad Nizar Hidayanto wrote:
Thank you for the comment,
I just wonder, how come i have two identic rows. I have set the
primary key and set it as a unique. That's why i take
a look at ctid (in real, i don't use this id. I just tried to trace
why i have two identic rows. After examining the physical
id using ctid, i found that the two identic rows differ in their ctid).
Having this case, can i conclude that postgre cannot guarantee the
uniqueness of primary key? or is it just a bug of old
version of postgre?
Well, it's certainly surprising your Postgres intallation is doing
that - it's one of the things Postgres is good at, but we lack
information to see what's really going on here.
You're mentioning you're using an old version, which one? The output
of "select version();" should do.
Can you show us the table definition with the primary key and the two
identical records you mentioned?
Many thanks for your help.
Nizar
=====
Tom Lane wrote:
Achmad Nizar Hidayanto <nizar@xxxxxxxxxxx> writes:
I implement database in my faculty using Postgre. I have a problem
with ctid in my tables. Let say, i have table STUDENT with #STU as
the primary key. I don't know what happend in this table, some
rows have exactly the same value ( i also have set the #STU as
unique). After tracing the table, i found that the two rows differ
in ctid value. As the impact, my application cannot operate well.
There are some known bugs in older PG releases that could lead to
duplicate rows (actually, to multiple versions of a row all being
seen as live). If you're not on the latest minor version of your
release series, update. regards, tom lane
Alban Hertroys
--
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cut the trees and you'll see there is no forest.
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