Re: PL/pgSQL RENAME functionality in TODOs

On 2/1/07, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> imad <immaad(at)gmail(dot)com> writes:
> > OK, so renaming does not work in the same block.
> > You can rename a vairable in a nested block and thats why it works for OLD/NEW.
>
> > BTW, what is the purpose behind it? Declaring a variable in a block
> > and quickly renaming it does not make sense to me.
>
> I agree it's pretty useless; but if we're gonna forbid it then we should
> throw a more sensible error than "syntax error".
>
> Actually, it seems to me that it works in the nested-block case only for
> rather small values of "work":
>
> regression=# create function foo() returns int as $$
> regression$# declare
> regression$# x int := 1;
> regression$# begin
> regression$# x := 2;
> regression$# declare
> regression$# rename x to y;
> regression$# begin
> regression$# y := 3;
> regression$# end;
> regression$# return x;
> regression$# end$$ language plpgsql;
> CREATE FUNCTION
> regression=# select foo();
> ERROR: column "x" does not exist
> LINE 1: SELECT x
> ^
> QUERY: SELECT x
> CONTEXT: PL/pgSQL function "foo" line 10 at return
> regression=#
>
> Surely the variable's name should be x again after we're out of the
> nested block?

Yes, seems to be the only possible reason of renaming a variable.

--Imad
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