Re: which "where condition" I should use?

Posted in 1996

Systems Team — Thu, 21 Nov 1996 11:15:14 +0000 — source: Informix-list mailing list archive (1991-1998)

Madeline Wu wrote: > > Our engineer is ONLINE 5.0. > When I set explain on, the result is: > > 1) update tables set field="value" where uniqe_index_value > estimated cost: 1 > > 2) update tables set field="value" where rowid=num > estimated cost: 13288 > > Is it mean "where condition" use uniqe index value > is better than use rowid ?? I would advise against using rowid for identifying rows. It is an "internal" field, with no specific meaning to the (logical) record concerned. Thus its value is not preserved if the table is re-organized in any way. Also, I thought that Informix were removing/have removed(?) support for rowid in later versions of OnLine - True or False? Tim Kelly