Re: Foreign Key and Index

Jaret

So long as the FK column(s) is/are the leading column(s) of another index (due to PK constraint or a explicit index) you won't need to index it/them.

Example
PK - columns a,b,c,d

No index needed if
FK - columns a,b
FK - columns a

Index needed if

FK - columns a,c - because no b in FK
FK - columns b - because b is not leading column of PK index
FK - columns e,a - because e in not in PK index

Hope this helps

Andy

"Jaret Lafoudravecmonhai" <nospam_at_nospam.com> wrote in message news:aiarlp$17p$1_at_reader1.imaginet.fr...
> Hello,
>
> I must create some indexes on foreign keys to avoid some locing problems.
>
> Does the column indexes must be exactly the same as FK (exactly the same
> column, not more and same order) ? I've got a lot of existing index (PK
and
> other) including the FK column (but not the same order and more columns),
> and i don't want to make redundancy.
>
>
> Ludo
>
>
>
>
>
Received on Thu Aug 01 2002 - 05:02:32 CDT