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postgresqlplpgsqlrecord

Postgresql - testing RECORD types (for fields or null)


I am having problems dealing with plpgsql and RECORD types.

Does anyone know of a way to simply test a returned RECORD type to know if it was set or not?

Basic Pattern:

A function returns a RECORD and where it may be unset (i.e. select into returned no records) or it is set to a single record.

create or replace function blah()
returns RECORD as $$
declare
  rec RECORD;
begin
   rec := row(null); --Do not want to hear about it not being assigned
   select *, status_field into rec ... ;
   if found then
       raise notice '%', rec.status_field is not null   --prints 't'
   end if

   if not found then
       raise notice '%', rec.status_field is not null   --Throws Error (I just want it to say 'f'
   end if; 
end; $$

create or replace function callblah()
returns text as $$
declare
  rtText text;
  blahRec RECORD;
begin
 blahRed := blah(...);

 -- what test can I do to determine if record is set or not.
 -- Try: if blah is not null then -- nope always returns false for is null and is not null
 -- Try: if blah.status is not null then -- nope throws error on field not existing
 -- What test condition do I need to add here to simply test if record is either (NOT FOUND) or (FOUND where field will exist).
 ...
 end if
end; $$

Solution

  • Ah.. is null operator on RECORD is (all fields null), and not is null (all fields not null). As I have some fields null I need to do

    if blah is null then
       -- No record found
    else
       if blah.status is not null then
       -- Record found with field I want
       end if;
    end if;