I have a customer table which has lots of infomation (bank, expense, income, address, properties, ....). It is too big in my view. So I decided to split it into few smaller tables: customer, expense, income, address.
1. my decision is good or not?
2. the customer table has a custId as its primary key. For all other smaller tables, I can use the custId as its primary key, or I can declare a different primary key for those smaller tables and use the custId as their foreign key. Which way is better?