Unique Index vs. Unique Constraint

On Fri, 10 Oct 2003 13:59:38 -0500, "Thomas LeBlanc"
<thomasatiem@hotmail.com> wrote:

Does a Unique Constraint build a unique index?

Yes.

What is the difference?

A constraint is an abstract concept, an index is an implementation
detail.

Servus
Manfred

On Fri, 10 Oct 2003, Thomas LeBlanc wrote:

Does a Unique Constraint build a unique index?

What is the difference?

None that I know of.

Then what is the difference in these two statements?

alter table Table1
add constraint Table1_UC1
unique (Field1, Field2)

and

create unique index Table1_Field1Field2
on Table1 (Field1, Field2)

Thanks,
Thomas LeBlanc

From: Dennis Gearon <gearond@fireserve.net>
To: Thomas LeBlanc <thomasatiem@hotmail.com>
Subject: Re: [GENERAL] Unique Index vs. Unique Constraint
Date: Fri, 10 Oct 2003 15:16:12 -0700

Uniquely so!

Thomas LeBlanc wrote:

Does a Unique Constraint build a unique index?

What is the difference?

Thanks,
Thomas LeBlanc

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scott.marlowe wrote:

On Fri, 10 Oct 2003, Thomas LeBlanc wrote:

Does a Unique Constraint build a unique index?

What is the difference?

None that I know of.

A different implementation of UNIQUE constraint might allow
deferrability, what our index solution does not ... yet.

Jan

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