cascade delete from child table
You can cascade action by defining a Foreign Key to those tables.
Here is an example from Postgresql documentation

CREATE TABLE products (
    product_no integer PRIMARY KEY,
    name text,
    price numeric
);

CREATE TABLE orders (
    order_id integer PRIMARY KEY,
    shipping_address text,
    ...
);

CREATE TABLE order_items (
    product_no integer REFERENCES products ON DELETE CASCADE,
    order_id integer REFERENCES orders ON DELETE CASCADE,
    quantity integer,
    PRIMARY KEY (product_no, order_id)
);


Here, deleting product or order deletes all corresponding items in order_items. You can apply the same for your case.

In case you want to delete all items in primary table and delete corresonding record, it is possible with Truncate cascade. Something like

TRUNCATE TABLE products CASCADE

This will delete all data in products plus all dependent tables.

Apart form these two, you have to somehow manage the deletion yourself. I would in that case use scripting language, and I don't know much about PL/SQL