CASCADE DELETE just once

If you really want DELETE FROM some_table CASCADE; which means "remove all rows from table some_table", you can use TRUNCATE instead of DELETE and CASCADE is always supported. However, if you want to use selective delete with a where clause, TRUNCATE is not good enough.

USE WITH CARE - This will drop all rows of all tables which have a foreign key constraint on some_table and all tables that have constraints on those tables, etc.

Postgres supports CASCADE with TRUNCATE command:

TRUNCATE some_table CASCADE;

Handily this is transactional (i.e. can be rolled back), although it is not fully isolated from other concurrent transactions, and has several other caveats. Read the docs for details.

No. To do it just once you would simply write the delete statement for the table you want to cascade.

DELETE FROM some_child_table WHERE some_fk_field IN (SELECT some_id FROM some_Table);
DELETE FROM some_table;