Thank you for the insight. Do you have any idea about the request ?

Trond.

> Hi,
>
>> Yes, I know there are differences, but what they are specifically, I'm
>> not
>> sure.
>> I mention both since they are in the releaseNote :
>>
>> (1.5) NULLs in unique constraints and indices
>> Dmitry Yemanov
>> .
>> ---
>> Can a Unique constraints rely on a non unique index, or on no indices at
>> all ? As you can see, I don't know what's
>> going on in the engine regarding unique constraints / unique indices.
>> But,
>> from an Application POV I can't really see any differences. Please set
>> me
>> strait if I'm wrong here.
>
> An Unique Constraint automatically creates an index, so there's no
> need to add additional indices.
>
> An Unique Index is just that. An unique index.
>
> An Unique Constraint is a candidate key for a table - that means that
> it can be used in a Foreign Key Constraint definition -> FKs can
> point to columns that make up an Unique Constraint or the Primary
> Key Constraint of a table.
>
> So, one can say that an index is something physical (used to quickly
> look up table data) while a constraint is something logical.
>
>
> With regards,
>
> Martijn Tonies
> Database Workbench - developer tool for InterBase, Firebird, MySQL & MS
> SQL
> Server.
> Upscene Productions
> http://www.upscene.com
>
>
>
>
> Yahoo! Groups Links
>
>
>
>

--
Trond.