"Malcolm Dew-Jones" <yf110_at_vtn1.victoria.tc.ca> wrote in message
news:420f964e_at_news.victoria.tc.ca...
> vertigo (ax178_at_wp.pl) wrote:
> : Hello
>
> : Does oracle create automaticly indexes on not null columns ?
>
> No.
>
> But if you define constraints on a column then oracle may implement that
> constraint using an index on the column.
>
> Prime example being a primary key - it must be unique and a unique index
> is used to enforce that - so in that case those columns will be in an
> index. Also in that case, the columns involved will end up being not null
> columns.
Isn't this the *only* such example. As such I'd view it as an exception.
Incidentally if the column is already indexed (even with a non-unique key)
then the index won't be created (and more to the point) dropped with the
constraint.
--
Niall Litchfield
Oracle DBA
http://www.niall.litchfield.dial.pipex.com
Received on Sun Feb 13 2005 - 12:23:47 CST
