在同一用户的地址列表中获取默认地址的存储过程

Question

My use case is to store multiple addresses for a customer, and to be able to designate a single customer's address as the customer's default address.

I have three tables; customer (contains customer details), address (contains address details) and customer_address (maps customers to their addresses). In customer_address I have a field, is_default , that, allows the address to be designated as the default address for one customer (using is_default =1).

Is it possible to write a stored procedure that returns the default address for a given customer?

Answer 1

Assuming that you leave your database design as-is with the is_default field in the customer_address table, the query to return the default address might look something like below. It would be trivial to turn this query into a stored procedure (the only parameter needed would be the ID of the customer for whom you wish to return their defulat address):

SELECT a.*
FROM customer c
  JOIN customer_address ca ON ca.customer_id = c.id
  JOIN address a ON a.id = ca.address_id
WHERE ca.is_default = 1;

If you change your database design to store the default address ID in the customer record, where perhaps it should be, the query is simplified:

SELECT a.*
FROM customer c
  JOIN address a ON a.id = c.default_address_id;

Of course, storing the default address in the customer record may make other aspects of your application more difficult, such as adding or removing addresses to/from a customer.