Thread: Re : pg_dump, serial

Hi Tom,

I have read the given links, and I understand the reasons.

Still, I am a bit surprised to see no mention of this in the documentation of pg_dump. I would expect to see at least a
linestating that the colum declared with SERIAL will transformed to a SEQUENCE. 

I understand the point that pg_dump is there to recreate a database (so the file generated is to be read by
pg_restore).But developers also need a tool to reverse engineer a database and to get the creation scripts into file(s)
tobe read by humans, to easily have an overall view of the database ... and to be able to easily tweak it (I often
changecolums oreders in that script). So to me, pg_dump has two missions:  
 - to create files to be used by pg_restore (format = c or t)
 - to create SQL scripts (format = p) to be read by developers and to be modified by them.

It would have been nice to retain the possibility to have script with SERIAL (via an option), at the user risk (and
maybeif possible with warnings of potential problems for GRANT, etc ...). 
As far as I am concerned, I am not in the situation of having problems for using SERIAL (GRANT ...), and I prefer
scriptswith SERIAL as they are easier to read by a human, and also by programs (I have parsers looking for SERIAL to
generatecode for my Derby db). 

I don't want to start a war here, just giving ideas and the way I see things coming from other RDBMs (Sybase,
SQL-Server,Oracle). 


Have fun,
L@u
The Computing Froggy

----- Message d'origine ----
De : Tom Lane <tgl@sss.pgh.pa.us>
À : Laurent ROCHE <laurent_roche@yahoo.com>
Cc : pgsql-general@postgresql.org
Envoyé le : Vendredi, 2 Mars 2007, 17h03mn 18s
Objet : Re: [GENERAL] pg_dump, serial

Laurent ROCHE <laurent_roche@yahoo.com> writes:
> I understand (and I have read) that there have been changes and discussions about the way, pg_dump treats SERIAL
columnsin the latest versions(8.x). 
> However, I have not been able to get a document explaining exactly what the changes are and what's the reasoning
behindit, not even in the documentation. 
> Is there such a thing ?

See this thread and the earlier ones it refers to:
http://archives.postgresql.org/pgsql-hackers/2006-08/msg01250.php
The commit message here summarizes the changes:
http://archives.postgresql.org/pgsql-committers/2006-08/msg00376.php

            regards, tom lane









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Laurent ROCHE <laurent_roche@yahoo.com> writes:
> I have read the given links, and I understand the reasons.

> Still, I am a bit surprised to see no mention of this in the documentation of pg_dump. I would expect to see at least
aline stating that the colum declared with SERIAL will transformed to a SEQUENCE. 

There is no place in the pg_dump documentation where anything is
promised about the content of the scripts it emits, except that when
executed they are supposed to regenerate the content of your database.
We have always felt free to alter the exact commands that are issued to
accomplish that.  This case is not noticeably different from previous
pg_dump changes AFAICS.

In any case, the documentation of SERIAL itself makes the equivalence
clear enough:
http://www.postgresql.org/docs/8.2/static/datatype-numeric.html#DATATYPE-SERIAL

            regards, tom lane