Correction
The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/14/citext.html
Description:
"If you declare a column as UNIQUE or PRIMARY KEY, the implicitly generated
index is case-sensitive. So it's useless for case-insensitive searches, and
it won't enforce uniqueness case-insensitively."
I think the statement above is not correct. I tried creating a PK or unique
key index on a CITEXT column. It checks uniqueness in case-insensitivity.
Here is the error I got when I tried to add a duplicated value 'Des'.
DETAIL: Key (des)=(Des) already exists.
PG Doc comments form <noreply@postgresql.org> writes:
"If you declare a column as UNIQUE or PRIMARY KEY, the implicitly generated
index is case-sensitive. So it's useless for case-insensitive searches, and
it won't enforce uniqueness case-insensitively."
I think the statement above is not correct. I tried creating a PK or unique
key index on a CITEXT column. It checks uniqueness in case-insensitivity.
That paragraph is talking about what happens when you *don't* use citext.
regards, tom lane