Re: currval() within one statement

Richard Huxton wrote:
> sad wrote:
>> A. Kretschmer wrote:
>>
>>>> is it expected that the currval() changes its value between calls 
>>>> within one statement ?
>>
>>> Conclusion, don't call nextval() within a TRIGGER, and insert either
>>> nextval() for the column or omit this column.
>>
>> I only note that i still want to discuss the titled problem or to be
>> given an exact pointer to documentation regarding the currval() behavior
>> in the described situation, that i had.
> 
> Well, the page in the docs isn't hard to find -
>  http://www.postgresql.org/docs/8.2/static/functions-sequence.html
> 
> But surely it works exactly as you would expect it to.
> 
> nextval(S) advances the sequence and returns the new value
> 
> currval(S) returns the current value of sequence S, which is whatever 
> the previous call to nextval(S) returned. In the even you haven't called 
>  nextval(S) then it is undefined.

Then this is the question on the execution order of the statement 
INSERT...SELECT...

> What do you think should happen?

I had expected all the currval() calls to be called before all the 
triggers fired.