Re: Difference between UNIQUE constraint vs index

Problem number 6,534 with implementing an abstract concept such as an
RDB on a digital computer with an electro-magno-mechanical storage
system.

:p

--
Brandon Aiken
CS/IT Systems Engineer
-----Original Message-----
From: Tom Lane [mailto:tgl(at)sss(dot)pgh(dot)pa(dot)us]
Sent: Wednesday, February 28, 2007 11:03 AM
To: Brandon Aiken
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: [GENERAL] Difference between UNIQUE constraint vs index

"Brandon Aiken" <BAiken(at)winemantech(dot)com> writes:
> SQLite, MySQL, and MS Access each use indexes for unique constraints.
> Doesn't the SQL spec specify that CREATE INDEX can be used to create
> UNIQUE indexes?

No, there is no such command in the SQL spec. In fact the concept of an
index does not appear anywhere in the spec ... it's an implementation
detail.

regards, tom lane

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