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Re: Difference between UNIQUE constraint vs index - Mailing list pgsql-general

From Tom Lane
Subject Re: Difference between UNIQUE constraint vs index
Date
Msg-id 4211.1172678600@sss.pgh.pa.us
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In response to Re: Difference between UNIQUE constraint vs index  ("Brandon Aiken" <BAiken@winemantech.com>)
Responses Re: Difference between UNIQUE constraint vs index  ("Brandon Aiken" <BAiken@winemantech.com>)
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"Brandon Aiken" <BAiken@winemantech.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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