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@xxxxxxxxxxxxx] Sent: Wednesday, February 28, 2007 11:03 AM To: Brandon Aiken Cc: pgsql-general@xxxxxxxxxxxxxx Subject: Re: [GENERAL] Difference between UNIQUE constraint vs index "Brandon Aiken" <BAiken@xxxxxxxxxxxxxxx> 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 -------------------------------------------------------------------- ** LEGAL DISCLAIMER ** Statements made in this e-mail may or may not reflect the views and opinions of Wineman Technology, Inc. or its employees. This e-mail message and any attachments may contain legally privileged, confidential or proprietary information. If you are not the intended recipient(s), or the employee or agent responsible for delivery of this message to the intended recipient(s), you are hereby notified that any dissemination, distribution or copying of this e-mail message is strictly prohibited. If you have received this message in error, please immediately notify the sender and delete this e-mail message from your computer.
