ActiveRecord Tutorial

Any ActiveRecord object can have a GUI interface added to it easily using visualruby. Using Ruby and ActiveRecord you can easily add, delete, and save records to a database. However, its considerably more difficult to edit records because there is no way to display the records on the screen. Visualruby solves that problem.

ActiveRecord objects can use the GladeGUI interface to add a GUI, just like any other class. You simply add this line to your class:

include GladeGUI

To illustrate adding a GUI, I’ll present a simple example of an existing ActiveRecord class named “Person:”

class Person < ActiveRecord::Base
end

This class will automatically access a table named people in the database. Also, ActiveRecord will scan the table to learn the names of the fields in the people table. So, there are several fields in this table even though they’re not listed in the class.

The people table consists of these fields:

name
address
phone
email

To add a GUI to the Person class, you need to add these lines of code:

class Person < ActiveRecord::Base
  include GladeGUI

  def show()
    load_glade(__FILE__)
    set_glade_all()
    show_window()
  end

end

Now the Person class is ready to be shown on the screen as a GUI. However, we still need to create a glade form to show the fields. In the visualruby IDE, you need to right-click on the Person.rb file to create a form using glade. You can see this done in the above video. When you create a glade form in visualruby, it will automatically be placed in the “glade” directory, so the method, GladeGUI#load_glade can find it.

Then you need to add 4 entry boxes with the names, name, address, phone, email to correspond to the names of the fields in the table.

When the glade file is finished, the load_glade method will load the glade form into memory, the set_glade_all() method will automatically fill all the form’s fields with their corresponding values (i.e. the entry box named “address” will be filled with the address field.) And the show_window() method will simply show the window on the screen:

Editing Records

The above glade form only shows the fields from the people table on the screen. If you want to edit the records you simply need to add a “Save” button to the form and attach code to it.

class Person < ActiveRecord::Base
  include GladeGUI

  def show()
    load_glade(__FILE__)
    set_glade_all()
    show_window()
  end

  def buttonSave__clicked
    get_glade_all()
    save
  end

end

The above example assumes that you’ve added a button named “buttonSave” to your glade form. You don’t need to use the Glib::Instaniatable#signal_connect method to connect a signal to the button. You only need to name the method according to visual ruby’s naming convention:

(method name= buttonSave__clicked. See Signals tutorial for more).

The get_glade_all() method will update the values for the ActiveRecord fields from the glade form. For example, if you edited the person’s email address on the screen, the get_glade_all() method would update the value of Person.email to the same value as the screen shows. The get_glade_all() method is simply the opposite of the set_glade_all() method. So the get_glade_all method updates the instance of Person, but not the physical database on the server. The save() method is from the superclass, ActiveRecord::Base, and it simply commits the cahnges to the actual database server.

You can also easily add a delete button that calls ActiveRecord::Base#delete.