RE: [LUG] postgresql inserts

["Henshall, Stuart - Design & Print" <SHenshall@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>]

Hi,

As long as they are on a different connection there should be no problem as currval returns the last sequence value that the connection requested, of course if multiple users can use a connection through some sort of pooling this wont work. Of course nextval will work under these circumstances as well.

I am unsure why you would want to lock the sequences as this would cause conntention whenever two transaction tried to use the sequence (eg for inserts). The following link explains a bit about these functions:

http://www.postgresql.org/docs/view.php?version=7.3&idoc=1&file=functions-sequence.html

Cheers,

- Stuart

-----Original Message-----
From: Robert Nowik [mailto:robert.nowik@xxxxxxxxxxxxxxx]
Sent: 14 April 2003 16:49
To: list@xxxxxxxxxxxx
Subject: Re: [LUG] postgresql inserts

Hi, thanks for this idea.

As this reqiures 2 SQL commands, I am worried that there may be some problems if this procedure should be run by a different user inbetween these commands. I would consider transaction locking, however sequences values are not locked. Any ideas on how to secure this?

 

Thanks

Rob Nowik

 

 

----- Original Message -----

From: Henshall, Stuart - Design & Print

To: 'list@xxxxxxxxxxxx'

Sent: Monday, April 14, 2003 4:21 PM

Subject: RE: [LUG] postgresql inserts

You cand o:

SELECT currval('sequence_name') as cv;

The default sequence names for serial are, IIRC: <table_name>_<column_name>_seq

Alternativley you can do a nextval('seq_name') then insert that value (which is the way I prefer).

Cheers,

- Stuart

 

-----Original Message-----
From: chris [mailto:chris@xxxxxxxxxxxxxxxxxx]
Sent: 14 April 2003 16:24
To: list@xxxxxxxxxxxx
Subject: RE: [LUG] postgresql inserts

Does postgres have stored procedures or similar?

-----Original Message-----
From: owner-list@xxxxxxxxxxxx [mailto:owner-list@xxxxxxxxxxxx]On Behalf Of Robert Nowik
Sent: 14 April 2003 16:05
To: List@xxxxxxxxxxxx
Subject: [LUG] postgresql inserts

Hi,

Not really a linux specific problem, but in postgreSQL i am trying to have an INSERT statement, that has a serial as the only unique identifier. This serial is not set by myself (postgres handles this) but as this is the only unqiue identifier, i need to return it as I do the insert. Any suggestions?

 

 

Cheers

 

Rob Nowik



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