Accidentally detected all data from a table, insert dummy data to table using loop psql - postgresql

Question

I had accidentally deleted most of the rows in my Postgres table (data is not important its in my test environment, but I need a dummy data to be insert in to these table).
Let us take three tables,
MAIN_TABLE(main_table_id, main_fields)
ADDRESS_TABLE(address_table_id, main_table_id, address_type, other_fielsds)
CHAID_TABLE(chaid_table_id,main_table_id, shipping_address_id, chaild_fields)
I had accidentally deleted most of the data from ADDRESS_TABLE.
ADDRESS_TABLE has a foreign key from MAIN_TABLE ,i.e. main_table_id. for each row in MAIN_TABLE there is two entries in ADDRESS_TABLE, in which one entry is its address_type is "billing/default" and other entry is for address_type "shipping".
CHAID_TABLE has two foreign keys one from MAIN_TABLE, i.e. main_table_id and other from ADDRESS_TABLE i.e., shipping_address_id. this shipping_address_id is address id of ADDRESS_TABLE, its address_type is shipping and ADDRESS_TABLE.main_table_id = CHAID_TABLE.main_table_id.
These are the things that I needed.
I need to create two dummy address entries for each raw in MAIN_TABLE one is of address type "billing/default" and other is of type "shipping".
I need to insert address_table_id to the CHAID_TABLE whose ADDRESS_TABLE.main_table_id = CHAID_TABLE.main_table_id. and addres_type ="shipping"
if first is done I know how to insert second, because it is a simple insert query. I guess.
it can be done like,
UPDATE CHAID_TABLE
SET shipping_address_id = ADDRESS_TABLE.address_table_id
FROM ADDRESS_TABLE
WHERE ADDRESS_TABLE.main_table_id = CHAID_TABLE.main_table_id
AND ADDRESS_TABLE.addres_type ='shipping';
for doing first one i can use loop in psql, ie loop through all the entries in MAIN_TABLE and insert two dummy rows for each rows. But I don't know how to do these please help me to solve this.

Answer 1

I hope your solution is this, Create a function that loop through all the rows in MAIN_TABLE, inside the loop do the action you want, here two insert statement, one issue of this solution is you have same data in all address.
CREATE OR REPLACE FUNCTION get_all_MAIN_TABLE () RETURNS SETOF MAIN_TABLE AS
$BODY$
DECLARE
r MAIN_TABLE %rowtype;
BEGIN
FOR r IN
SELECT * FROM MAIN_TABLE
LOOP
-- can do some processing here
INSERT INTO ADDRESS_TABLE ( main_table_id, address_type, other_fielsds)
VALUES('shipping', r.main_table_id,'NAME','','other_fielsds');
INSERT INTO ADDRESS_TABLE ( main_table_id, address_type, other_fielsds)
VALUES('billing/default',r.main_table_id,'NAME','','other_fielsds');
END LOOP;
RETURN;
END
$BODY$
LANGUAGE plpgsql;
SELECT * FROM get_all_MAIN_TABLE ();