create child table function using cursor in postgresql - postgresql

Question

CREATE FUNCTION create_child1()
RETURNS TABLE(sys_user_id integer,
sys_service_id integer
)
LANGUAGE 'plpgsql'
COST 100
VOLATILE
ROWS 1000
AS $BODY$
DECLARE
curr_id CURSOR IS
SELECT id FROM users WHERE id in (3089,3090,3091,3092);
v_id bigint;
BEGIN
OPEN curr_id;
LOOP
FETCH curr_id INTO v_id;
EXIT WHEN not found ;
EXECUTE format('
CREATE TABLE IF NOT EXISTS %I (
sys_user_id integer,
sys_service_id integer
id bigint NOT NULL primary key
)
INHERITS (telemetry_master)
WITH (
OIDS=FALSE
)', 'telemetry_' || v_id);
end loop;
close curr_id;
fetch next from curr_id into v_id;
END
$BODY$ LANGUAGE plpgsql;

Answer 1

You do not need an explicit cursor in your function. You can use a simple FOR ... IN ... LOOP.
It is unclear what you want to return from the function. For example, it can return a readable text about each created table.
CREATE OR REPLACE FUNCTION create_child1()
RETURNS SETOF text LANGUAGE plpgsql
AS $BODY$
DECLARE
v_id int;
BEGIN
FOR v_id IN 3089..3092 LOOP
EXECUTE format('
CREATE TABLE IF NOT EXISTS telemetry_%s (
sys_user_id integer,
sys_service_id integer,
id bigint NOT NULL primary key
)
INHERITS (telemetry_master)', v_id);
RETURN NEXT format('telemetry_%s created.', v_id);
END LOOP;
END $BODY$;
Use:
SELECT create_child1();
create_child1
-------------------------
telemetry_3089 created.
telemetry_3090 created.
telemetry_3091 created.
telemetry_3092 created.
(4 rows)
If the ids are not consecutive you can use unnest(), e.g.:
FOR v_id IN SELECT id FROM unnest(array[3000,3001,3020,3021]) AS id LOOP