Borrar grupo de tablas PostgreSQL sin que interfieran las restricciones

Estuve algunos días dando vuelta para poder eliminar un grupo de tablas exceptuando solo un grupo en especifico, un grupo muy pequeño de hecho. Conseguí mucha información pero nada lo suficientemente acertado ni practico para aplicarlo así que con esas gotas que fui consiguiendo construí esto

<

DO

$$

DECLARE

v_table VARCHAR;

v_sql_string VARCHAR;

v_exclude_table VARCHAR[] := ARRAY['field1', 'field2', 'field3'];

v_i INTEGER;

v_num INTEGER;

BEGIN

SELECT INTO v_num count(relname)

FROM pg_class c

JOIN pg_namespace nsp ON c.relnamespace = nsp.oid

WHERE c.relname <> ALL(v_exclude_table)

AND nsp.nspname = 'public'

AND relhasindex = 't';

FOR v_i IN 1..v_num

LOOP

SELECT c.relname

INTO v_table

FROM (

SELECT pg_constraint.confrelid, COUNT(confrelid) as total FROM pg_constraint, pg_class WHERE

pg_class.oid = pg_constraint.conindid

GROUP BY pg_constraint.confrelid

) AS rest

RIGHT JOIN pg_class c ON rest.confrelid = c.oid

JOIN pg_namespace nsp ON c.relnamespace = nsp.oid

WHERE c.relname <> ALL(v_exclude_table)

AND nsp.nspname = 'public'

AND relhasindex = 't'

ORDER BY 

CASE WHEN rest.total IS NULL THEN 0 END, rest.total LIMIT 1;

IF EXISTS(SELECT 1 FROM pg_class c

JOIN pg_namespace nsp ON c.relnamespace = nsp.oid

WHERE c.relname <> ALL(v_exclude_table)

AND nsp.nspname = 'public'

AND relhasindex = 't' ORDER BY c.oid desc LIMIT 1) THEN

v_sql_string := 'DROP TABLE ' || v_table;

EXECUTE v_sql_string;

RAISE NOTICE 'Table %s Deleted',v_table;

ELSE

RAISE NOTICE 'Table %s Not Deleted',v_table;

END IF;

END LOOP;

END

$$

>

Estos script SQL me permitieron buscar las tablas del esquema que me interesaba y organizarla de tal forma que las restricciones no interrumpieran su eliminación.

/*

SELECT relname

FROM pg_class c

JOIN pg_namespace nsp ON c.relnamespace = nsp.oid

WHERE c.relname <> ALL(ARRAY['field1', 'field2', 'field3'])

AND nsp.nspname = 'public'

AND relhasindex = 't';

SELECT c.relname, rest.total, c.oid

FROM (

SELECT pg_constraint.confrelid, COUNT(confrelid) as total FROM pg_constraint, pg_class WHERE

pg_class.oid = pg_constraint.conindid

GROUP BY pg_constraint.confrelid

) AS rest

RIGHT JOIN pg_class c ON rest.confrelid = c.oid

JOIN pg_namespace nsp ON c.relnamespace = nsp.oid

WHERE c.relname <> ALL(ARRAY['field1', 'field2', 'field3'])

AND nsp.nspname = 'public'

AND relhasindex = 't'

ORDER BY 

CASE WHEN rest.total IS NULL THEN 0 END, 

    rest.total;

*/

Entre tanto buscar perdí muchas de las referencias...

https://stackoverflow.com/questions/29913856/how-to-drop-a-table-based-on-if-condition-in-postgres
https://stackoverflow.com/questions/4326343/mysql-left-join-order-by-null-values-to-the-end