Re: Fact Table Question

Joseph Wilson wrote:

> Oracle version 8.1.7
>
> The column names will not be in order most of the time. I would say that it
> would only be about 10% of the time that the columns will be in the order of
> the primary key order.
>
> "DA Morgan" <damorgan_at_exxesolutions.com> wrote in message
> news:3E828AF2.CC7F2F0D_at_exxesolutions.com...
> > Joseph Wilson wrote:
> >
> > > I have a fact table which is composed of 5 foreign keys and one numeric
> > > value. Is there any benefit to creating a primary key bitmap index on
> the 5
> > > foreign key columns together vs just creating 5 individual bitmap
> indexes on
> > > the foreign keys? I know the primary key will perform the unique
> checking,
> > > but it seems like the individual indexes will be better used for
> querying.
> > > Am I missing something? Is there a reason to go one way or the other?
> > >
> > > Thanks,
> > > Joe
> >
> > What version of Oracle?
> >
> > How often will the queries use WHERE clauses with column names in an order
> other
> > than the one in the proposed composite constraint?
> >
> > Daniel Morgan
> >

Then a composite index will be useful 10% of the time. That alone should answer your question.

Though I will tell you that dynamically creating WHERE clauses that do not correspond with the ability of Oracle to use indexes is a great way to create a lousy application.

Daniel Morgan Received on Thu Mar 27 2003 - 19:10:39 CST