Re: using sequences

Hi Erik,

Erik Price wrote:
> I have read the manual about sequences and I thought I understood both
> their purpose and how to use them.  When I perform inserts, the sequence
> is updated appropriately.  However, I can't seem to directly access the
> sequence myself.  I always seem to get this message:
>
> be_db=# select currval('news_news_id_seq');
> ERROR:  news_news_id_seq.currval is not yet defined in this session
>
> Can someone explain what is going on?

This is a FAQ. Although it is mentioned clearly in the documentation,
it is often overread:

currval() is only valid after nextval() in your transaction.
This is to get the id for your last insert or whatever and
_not_ the id of some other insert concurrently running.

Does this help?

Regards
Tino Wildenhain