<sequence_name>.sequence_name != <sequence_name>?

Started by Ed L.almost 23 years ago3 messages
#1Ed L.
pgsql@bluepolka.net

When a sequence is created in 7.3.2, it appears you get a new table for each
sequence object. Is it ever possible for the sequence_name in a sequence
relation not to match the name of the relation itself?

For example, suppose I create a table:

CREATE TABLE t1(id serial);

A new relation called 't1_id_seq' is created where

t1_id_seq.sequence_name = 't1_id_seq'

Is that always true?

Ed

#2Tom Lane
tgl@sss.pgh.pa.us
In reply to: Ed L. (#1)
Re: <sequence_name>.sequence_name != <sequence_name>?

"Ed L." <pgsql@bluepolka.net> writes:

When a sequence is created in 7.3.2, it appears you get a new table for each
sequence object. Is it ever possible for the sequence_name in a sequence
relation not to match the name of the relation itself?

ALTER TABLE RENAME on a sequence doesn't update the sequence_name.

I think someone looked at doing that update, but we concluded it was too
messy (mainly because ALTER RENAME is transactional but updates to a
sequence tuple aren't).

In general I'd counsel that you should ignore the sequence_name field
anyway. It's vestigial.

regards, tom lane

#3Ed L.
pgsql@bluepolka.net
In reply to: Tom Lane (#2)
Re: <sequence_name>.sequence_name != <sequence_name>?

On Friday April 4 2003 10:24, Tom Lane wrote:

"Ed L." <pgsql@bluepolka.net> writes:

When a sequence is created in 7.3.2, it appears you get a new table for
each sequence object. Is it ever possible for the sequence_name in a
sequence relation not to match the name of the relation itself?

In general I'd counsel that you should ignore the sequence_name field
anyway. It's vestigial.

A related question: Is there a single generalized SQL query which can yield
the set of (sequence_name, last_value) pairs for all sequence objects? The
fact that each sequence is its own relation seems to block that, and the
query constructed from grabbing sequence names from pg_class gets quite
long for more than just a few sequence objects...

Ed