postgresql - create trigger in PosgreSQL -

so found example:

create function eager.account_insert() returns trigger   security definer   language plpgsql $$   begin     insert eager.account_balances(name) values(new.name);     return new;   end; $$;  create trigger account_insert after insert on accounts     each row execute procedure eager.account_insert(); 

the thing can't understand: function eager.account_insert() not take arguments, however, operates variable new. returns it, should't return trigger?

also, this: insert eager.account_balances(name), not record chosen, this?

the new (and old when it's update statement) record you're inserting or updating. can columns , whatever want them. many times before insert triggers check valid values etc.

the function must return record same columns table, or null if insert should not happen (usually instead triggers).

the insert statement regular insert 1 column specified of table , value taken newly inserted record's column name.

the documentation explains triggers well.