Re: constraitnt on case sensetive and case insensetive columns

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A Bruce wrote:

| hello,
|
| I am attempting to convert a oracle database to postgresql and I am having
| some problems creating a constraint across multiple columns which are a
| mixture of case insensitive and case sensitive.
|
| The original oracle database created an index with:
| CREATE UNIQUE INDEX hatidx ON hats (upper(name), upper(server), login);
|
| However postgresql can handle multiple columns in the index, or one function,
| but not multiple functions, thus this fails.
|
| Queries are only done using the actual values, so the presence of the
| index is not required for performance reasons, and exists only to
| enforce the constraint that (upper(name), upper(server), login) is a
| unique tuple. Is there anyway to create a constraint which will check
| this? I suspect it would be possible to create a trigger to check this,
| however this is a little ugly, and i would like something more similar to
| to the original if possible.
|
| Any suggestions as to how to approach this would be greatly appreciated,
| -bruce
|

I'm using the 7.4.x version and what you ask for is supported:

regression=# create table test ( a varchar, b varchar, c varchar );
CREATE TABLE
regression=# create unique index test_idx on test ( upper(a), upper(b), c);
CREATE INDEX

Regards
Gaetano Mendola

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