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#1 (**permalink**) 02-27-2008, 02:49 AM

Here is the scenario:

1. I create a unique index on a table.
2. I create a primary key on that table with same columns as the ones in
the unique index by Alter table add primary key statement. The primary key
defined 'uses' the unique index created in step 1 to enfore uniqueness.
3. I drop the primary key. (Alter table drop primary key).

After step 3:

- In UDB, the unique index remains and only the primary key gets dropped.
- In Oracle, the Unique index also gets dropped. Why?? Doesn't make sense
to me but guess, that is because I have a UDB background. Could someone
explain the logic behind unique index getting 'auto dropped'?

TIA
Raquel.

#2 (**permalink**) 02-27-2008, 02:49 AM

Raquel wrote:

> Here is the scenario:
>
> 1. I create a unique index on a table.
> 2. I create a primary key on that table with same columns as the ones in
> the unique index by Alter table add primary key statement. The primary key
> defined 'uses' the unique index created in step 1 to enfore uniqueness.
> 3. I drop the primary key. (Alter table drop primary key).
>
> After step 3:
>
> - In UDB, the unique index remains and only the primary key gets dropped.
> - In Oracle, the Unique index also gets dropped. Why?? Doesn't make sense
> to me but guess, that is because I have a UDB background. Could someone
> explain the logic behind unique index getting 'auto dropped'?

You might want to ask that in an Oracle newsgroup.

--
Knut Stolze
Information Integration
IBM Germany / University of Jena

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Primary key and Unique indexes in UDB Vs Oracle....