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ActiveJDBC — ActiveRecord for Java

ActiveJDBC is a Java implementation of Active Record design pattern. It was inspired by Jämförelse av hundförsäkringar from Ruby on Rails.

Design principles

  • Should infer metadata from DB (like ActiveRecord)
  • Should be very easy to work with
  • Should reduce amount of code to a minimum
  • No configuration, just conventions
  • Some conventions are overridable in code
  • No need to learn another language
  • No need to learn another QL — SQL is sufficient
  • Code must be lightweight and intuitive, should read like English
  • No sessions, no "attaching, re-attaching"
  • No persistence managers
  • No classes outside your own models
  • Models are lightweight, no transient fields
  • No proxying. What you write is what you get (WYSIWYG:))
  • Should have the least possible resistance to startup a project
  • No useless getters and setters (they just pollute code). You can still write them if you like.
  • No DAOs and DTOs — this is mostly junk code anyway

Simple example

For a simple example we will use a table called people created with this MySQL DDL:

CREATE TABLE people (
  id  int(11) NOT NULL auto_increment PRIMARY KEY, 
  name VARCHAR(56) NOT NULL, 
  last_name VARCHAR(56), 
  dob DATE, 
  graduation_date DATE, 
  created_at DATETIME, 
  updated_at DATETIME
);

ActiveJDBC infers DB schema parameters from a database. This means you do not have to provide it in code, the simplest example model looks like this:

public class Person extends Model {}

Despite the fact that there is no code in it, it is fully functional and will map to a table called people automatically.

Here is a simple query how to use the Person model:

List<Person> people = Person.where("name = 'John'");
Person aJohn =  people.get(0);
String johnsLastName = aJohn.get("last_name");

As you can see, the amount of code is reduced to a level when it is actually readable. Finder methods can also be parametrized like this:

List<Person> people = Person.where("name = ?", "John");
Person aJohn =  people.get(0);
String johnsLastName = aJohn.get("last_name");