Still don't understand why you can't have a date index and have a where
date is greater than... (see my previous post)

On Fri, 2010-11-19 at 16:42 +0100, Zd wrote:
> I already have a primary key on Calendar - let's call it EventID.
>
> The question is which is going to be faster?
>
> SELECT StartTime, EndTime, Description, ReminderNum, ReminderType, ReminderDir FROM Calendar WHERE UserID = ... AND IsReminder = 1
>
> - OR -
>
> SELECT C.StartTime, R.ReminderNum, R.ReminderType, R.ReminderDir FROM Reminders R LEFT JOIN Calendar C ON R.EventID = C.EventID WHERE C.UserID = ...
>
> Also my problem is:
>
> Table Calendar contains let's say 1.000.000 records. It has primary key EventID. EventID goes from 1 to 1.000.000
> Table Calendar has a field called UserID. UserID varies between 0 and 5.
>
> If I put an index on UserID, how much will it speed up this query:
>
> SELECT ... FROM Calendar WHERE UserID = 3
>
> I've read that indexes with low selectivity are basically worthless in Firebird. So how can I make that query faster?
>
> Thanks!
>
> ----- Original Message -----
> From: Peter Faulks
> To: firebird-support@yahoogroups.com
> Sent: Friday, November 19, 2010 3:26 PM
> Subject: Re: [firebird-support] DB design best practices - which solutionisfaster?
>
>
>
> I'm still not 100% sure what it is you are doing....
>
> Sounds like you need a separate table then. Join the two on a integer
> primary key - use create generator and select gen_id() to create a
> sequence. (it is always generally a good thing to make primary keys
> meaningless)
>
> When does a reminder expire? would you then delete it from the table?
>
> Why would a reminder be set for after the event?
>
> On Fri, 2010-11-19 at 14:15 +0100, Zd wrote:
> > Hello Set,
> >
> > The problem is that reminders can be set x hours/days/weeks etc.
> > before or after an event. Thus I can't say that I only check for
> > reminders 1 week before or after the event.
> >
> > I'm also worried about querying of UserIDs, ie.: SELECT ... FROM
> > Calendar WHERE UserID = ...
> >
> > If I have a table with 200.000 records and only 4 UserIDs, how slow is
> > that going to be?
> >
> > Thanks,
> > Zd
> >
>
>
>
>
>
> [Non-text portions of this message have been removed]
>
>
>
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