Re: Help with using Triggers MySql/Innodb
Steven Lembark <[email protected]>
| Newsgroups | gmane.comp.lang.perl.modules.dbi.general |
|---|---|
| Organization | Workhorse Computing |
| Message-ID | <[email protected]> |
On Thu, 26 Feb 2015 15:31:56 +0000 "Martin J. Evans" <[email protected]> wrote: > I would actually suggest you don't use a trigger for this and also > that you don't store the count of people in a house in a column in > the house table. You can always calculate how many people there are > in a house but if you use triggers or some other mechanism to keep > the count you run the risk of the count not actually agreeing with > the rows with that house id. In other words, I think this is > generally bad design. You could get a one-step summary using a view that does a select with count(1) as "people" from a join of houses and people, grouped by the house. That leaves the houses and people separate and still gives you one-stop shopping for the houses with accurate counts. -- Steven Lembark 3646 Flora Pl Workhorse Computing St Louis, MO 63110 [email protected] +1 888 359 3508