Question

Take my domain class for example

public class Person
{
  private Integer id;
  private String name;
  private String address;
  private String telephone;

  //Accessors here..
}

This is great for storing 1 instance of a given Person, however, the name for example would most likely change over time, and I would like to retain any previous values, I may wish to see what addresses this person has lived at over the past 10 years.

What are my options for doing this? This is a Java web app so I could potentially have an AUDIT_LOG table on my schema, but that doesn’t sound a very reliable way of keeping track of these changes

Another thought is to have a PersonFamily and keep all instances of person, assuming the last item in the List is the most recent, such as..

 public class PersonFamily
 {
   private Integer id;
   private List<Person> persons;

   //Accessors here...
 }

Any suggestions on how I can achieve this? Is there a really clean and simple process I’ve missed?

Thanks

Answer 1

public class Person
{
  private Integer id;
  private String name;
  private Address address;

 }


public class Address {
  Integer id;
  String line1;
  String line2.
}

Then model this in your database either as :

Person Table

• id
• name

Address Table

• id
• line1
• line2

PersonAddressHistory Table with fields:

• id
• personId
• addressId
• activeDate

the last table maintains a list of the current and previous addresses associated with a person, with the current Address being the last entry (i.e. with max value of id).