Re: Case Insensitive CHECK CONSTRAINTs

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От Richard H
Тема Re: Case Insensitive CHECK CONSTRAINTs
Дата
Msg-id 20010314.20023500@client.archonet.com
обсуждение исходный текст
Ответ на Case Insensitive CHECK CONSTRAINTs  (Shaw Terwilliger <sterwill@sourcegear.com>)
Список pgsql-general
On 3/14/01, 6:59:18 PM, Shaw Terwilliger <sterwill@sourcegear.com> wrote
regarding [GENERAL] Case Insensitive CHECK CONSTRAINTs:

> I have a table with a TEXT field called "username".  I'd like to retain
the
> case of the data stored here, but I'd like all comparisons to be done
without
> regard to case.  Since all these accesses _should_ be done through
database
> functions, I can simply lower() the input values and compare.  I also
have
> an index created on lower(username), so lookups are quick.

> However, I'd also like to have some sort of table constraint to make sure
> alternate case "duplicate" records don't creep into the table.  Any tips?

As long as you have a UNIQUE index on lower(username) that will prevent
"duplicate"s. The UNIQUE applies to the index entry not the column(s) the
index applies to.

- Richard Huxton

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