Обсуждение: AW: Re: postgres TODO
> Thus spake Alessio Bragadini > > > > * Add function to return primary key value on INSERT > > > > > > I don't get the point of this. Don't you know what you > inserted? For > > > sequences there's curval() > > > > Mmmhhh... it means that we can assume no update to the > sequence value > > between the insert and the curval selection? > > We can within one connection so this is safe but there are > other problems > which I am not sure would be solved by this anyway. With > rules, triggers > and defaults there are often changes to the row between the > insert and the > values that hit the backing store. This is a general problem of which > the primary key is only one example. > > In fact, the OID of the new row is returned so what stops one > from just > using it to get any information required. This is exactly > what PyGreSQL > does in its insert method. After returning, the dictionary > used to store > the fields for the row have been updated with the actual > contents of the > row in the database. It simply does a "SELECT *" using the new OID to > get the row back. OID access is not indexed by default, only if the dba created a corresponding index. Thus OID access is a seq scan in a default environment. Andreas
At 15:58 10/07/00 +0200, Zeugswetter Andreas SB wrote: > >OID access is not indexed by default, only if the dba created a >corresponding >index. Thus OID access is a seq scan in a default environment. > Sticking my head out even further, this seems like a good reason to use 'insert/update...returning' - isn't the tuple already on the heap, and easily available at the end of the insert/update? ---------------------------------------------------------------- Philip Warner | __---_____ Albatross Consulting Pty. Ltd. |----/ - \ (A.C.N. 008 659 498) | /(@) ______---_ Tel: (+61) 0500 83 82 81 | _________ \ Fax: (+61) 0500 83 82 82 | ___________ | Http://www.rhyme.com.au | / \| | --________-- PGP key available upon request, | / and from pgp5.ai.mit.edu:11371 |/