Re: plpgsql - DECLARE - cannot to use %TYPE or %ROWTYPE for composite types

Jim Nasby <Jim(dot)Nasby(at)BlueTreble(dot)com> writes:
> On 3/3/16 4:51 AM, Pavel Stehule wrote:
>> CREATE TABLE a(a int);
>> CREATE TABLE b(a a.a%TYPE)
>>
>> And the people expecting the living relation between table a and table
>> b. So when I do ALTER a.a, then b.a should be changed. What if I drop
>> a.a or drop a?
>>
>> So this is reason, why I don't would this feature in SQL side.

> I don't buy that. plpgsql doesn't work that way, so why would this?
> *especially* with the %TYPE decorator.

Yeah. The %TYPE decorator doesn't work like that in the core parser
either: when you use it, the referenced type is determined immediately
and then it's just as if you'd written that type name to begin with.
I do not see a reason for any of these "type operators" to work
differently.

Another analogy that might help make the point is

set search_path = a;
create table myschema.tab(f1 mytype);
set search_path = b;

If there are types "mytype" in both schemas a and b, is myschema.tab.f1
now of type b.mytype? No. The meaning of the type reference is
determined when the command executes, and then you're done.

regards, tom lane