Re: PL/pgSQL RENAME functionality in TODOs

On 2/1/07, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> imad <immaad@gmail.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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