Database access code in objects constructor, or in data access object

Question

Given an object that is stored in a database, is it better to have the database access code in a constructor method, or a data access layer object? E.g. I have a Person class
public class Person{
int Id;
String name;
int age;
}When I want to read a person's details from the database, I could use a constructor something like this:
public Person(int id){
Connection con = getDatabaseConnection();
ResultSet rs = con.createStatement().executeQuery("Select name, age from person where person_id = " + id);
rs.next();
this.name = rs.getString(1);
this.age=rs.getInt(2);
}Or I could use a method in a data access object :
public Person getPerson(int id){
Person p = new Person();
Connection con = getDatabaseConnection();
ResultSet rs = con.createStatement().executeQuery("Select name, age from person where person_id = " + id);
rs.next();
p.setName(rs.getString(1));
p.setAge(rs.getInt(2));
return p;
}It seems to me that the constructor approach has two advantages
(1) the SQL code is kept in the relevant class (so if I want to add a field to Person, I only have to make changes to the Person class)
(2) I don't have to have a setter method for each field
Is one or other of these ways generally recognized as 'best practise'?

Answer 1

malcolmmc wrote:
But then, on the other hand, everytime a Person gains a new field that's two places you have to change it. if the persistence interface is written in terms of the object and uses ORM, I don't have to touch the implementation. all i have to do is update the object, the database, and the mapping - just like you and your home brew ORM.
besides, so what? i'd fear the resource leak, bad layering, more difficult testing more.
Actually lately I've used annotations to label setters with database field names and run a simple home brew ORM to convert rows into objects even when not using a more complex persistence manager.home brew ORM? why is that necessary when you can choose from hibernate, ibatis, jdo, jpa, etc.? that's just nuts.
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