HINTing on UPDATE foo SET foo.bar = ..;

Hi,

A common mistake is to try and qualify column references on the LHS of 
SET in UPDATE.  The error message can be a bit cryptic at times, too. 
I've attached a patch to try and improve the situation a bit:

=# create table foo(bar int);
CREATE TABLE

=# update foo set foo.bar = 1;
ERROR:  column "foo" of relation "foo" does not exist
LINE 1: update foo set foo.bar = 1;
                        ^
HINT:  Target column references in UPDATE must not be qualified

=# update foo set notfoo.bar = 1; -- no hint
ERROR:  column "notfoo" of relation "foo" does not exist
LINE 1: update foo set notfoo.bar = 1;
                        ^

=# update foo set foo.bar[1] = 1;
ERROR:  column "foo" of relation "foo" does not exist
LINE 1: update foo set foo.bar[1] = 1;
                        ^
HINT:  Target column references in UPDATE must not be qualified


I'll add this to the next CF, but feel free to bash it before that.


.marko