Обсуждение: array of composite type

-- create types to simulate input parameter

​​

CREATE TYPE kv_pair  AS(ckey text, cvalue text);

CREATE TYPE kv_pair_tab  as  (kv kv_pair[]);

load some values:

​​

    arr.kv[0] := CAST( row('var1','value of var1') AS kv_pair);

    arr.kv[1] := CAST( row('var2','value of var2') AS kv_pair);

    arr.kv[2] := CAST( row('var3','value of var3') AS kv_pair);

how can I write a FOREACH to retrieve the values:

var1, var2 and var3. 

​​

DO $$declare

   arr kv_pair_tab;

   kp kv_pair; 

begin

  foreach kp in array arr 

  loop

    RAISE NOTICE '#loop %', kp.ckey;

  end loop;

end$$;

ERROR:  FOREACH expression must yield an array, not type kv_pair_tab

I understand what the error message is telling me but. It wants an array, but the composite type,kv_pair IS the array. 

I've looked at dozens of examples but they are always slightly different than what I need.