Re: Allow COMMENT ON to accept an expression rather than just a string

> like (pseudo-code here)
>
>        execute('COMMENT ON foo IS $1', some_string);
>
> and let the out-of-line-parameter mechanism take care of quoting and
> escaping your string.  This doesn't work today, and I remember having
> seen complaints about that on the JDBC list.  So there's a use-case at
> least for allowing parameter symbols in place of string literals, if not
> fully general expressions.  But again, I think we'd want such a thing
> across all utility statements that can take string literals, not only
> COMMENT.

I afraid, this should have some not wanted impacts. When we allows
parametrisation in utility statements (and it should be nice), I
expect, so there will be people, that will write code like

CREATE OR REPLACE FUNCTION some_proc(tabname varchar)
RETURNS void AS $$
BEGIN CREATE TABLE tabname(a integer); -- will work INSERT INTO tabname VALUES(10); -- will not work
END;
$$ LANG ....

Now people know, so this cannot do it.

But the proc
CREATE OR REPLACE FUNCTION some_proc(tabname varchar)
RETURNS void AS $$
BEGIN EXECUTE 'CREATE TABLE $1(a integer)' USING tabname;

is more readable than EXECUTE 'CREATE TABLE ' || tabname || '(....

so this isn't too simple

regards
Pavel Stehule


>
>                        regards, tom lane
>