Re: [QUESTIONS] Business cases

Moved to pgsql-hackers@postgresql.org, where it should have been moved
*ages* ago


On Wed, 21 Jan 1998, Igor Sysoev wrote:

> > The result you're seeing is, IMHO, *correct*.
> >
> > The first row in the table, when the update is undertaken, produces a
> > duplicate key.  So you are getting a complaint which you SHOULD receive,
> > unless I'm misunderstanding how this is supposed to actually work.
> >
> > The "update" statement, if it is behaving as an atomic thing, effectively
>
> > "snapshots" the table and then performs the update.  Since the first
> > attempted update is on the first row it "finds", and adding one to it
> > produces "3", which is already on file, I believe it should bitch -
> > and it does.
>
> I'm not SQL guru and cannot tell how it must be.
> But it seems that Oracle and Solid allows update primary keys such way.

Connected to:
Oracle7 Server Release 7.3.3.0.0 - Production Release
With the distributed, replication and parallel query options
PL/SQL Release 2.3.3.0.0 - Production

SQL> create table one ( a integer primary key not null );

Table created.

SQL> insert into one values (2);

1 row created.

SQL> insert into one values (3);

1 row created.

SQL> insert into one values (1);

1 row created.

SQL> select * from one;

         A
----------
         2
         3
         1

SQL> update one set a=a+1;

3 rows updated.

SQL> select * from one;

         A
----------
         3
         4
         2

SQL>