CREATE EXTENSION IF NOT EXISTS template_fdw;
CREATE SERVER template FOREIGN DATA WRAPPER template_fdw;
CREATE FOREIGN TABLE foo(a int, b int) SERVER template;
-- should fail
INSERT INTO foo VALUES(10,20);
ERROR:  cannot insert into to table "public.foo"
DETAIL:  Table is template.
HINT:  Create temp table by statement "CREATE TEMP TABLE foo(LIKE public.foo INCLUDING ALL);"
SELECT * FROM foo;
ERROR:  cannot read from table "public.foo"
DETAIL:  Table is template.
HINT:  Create temp table by statement "CREATE TEMP TABLE foo(LIKE public.foo INCLUDING ALL);"
-- should work
CREATE TEMP TABLE foo(LIKE foo INCLUDING ALL);
INSERT INTO foo VALUES(10,20);
SELECT * FROM foo;
 a  | b  
----+----
 10 | 20
(1 row)