how to rename an unnamed uniqueness constraint?

Hello,

sorry if I post this message a second time,
but I don't know whether I was succesful the
first time, and since actually it's quite
urgent that I solve the problem described below,
I forward this message (again or not).

----- Forwarded message from Oliver Kullmann <O(dot)Kullmann(at)swansea(dot)ac(dot)uk> -----

Hello,

I have a table created with

CREATE TABLE Current_academic_year
(
year_id INT REFERENCES Academic_years,
CONSTRAINT year_id CHECK(year_id IS NOT NULL),
active BOOL NOT NULL,

UNIQUE(year_id),
UNIQUE(active)
)
;

Now I need to drop the constraint "UNIQUE(active)".
I tried variations of

ALTER TABLE current_academic_year DROP CONSTRAINT "???"

but I didn't succeed.

I'm using version 7.4.8.

Thanks in any case for your efforts!

Oliver

P.S. The "documentation" regarding the e-mail lists is
really the most arcane I've ever seen. I have no idea how
I'm supposed to post to a list, and/or to receive mails.
Of course I tried

http://mail.postgresql.org/mj/mj_wwwusr/domain=postgresql.org

and the help pages etc.: I always get "unsuccessful" back,
and the e-mails I get from "majordomo" just tell me that I
was unsuccessful (with registration).
And then there is "Sign in", "Sign out" ???
Just one paragraph about the idea how the average *novice*
should post a question and read the answer would be quite
useful.

----- End forwarded message -----