CUSTOM DATA TYPES

rubyonrails-talk
1

Hello,

I have this class in my Rails project :

class CreateModels < ActiveRecord::Migration   def self.up     create_table :models do |t|       t.string :model, :default => "Model", :limit => 10       t.string :description, :default => "short Description", :limit => 20       t.string :longdescription, :default => "long Description", :limit => 40       t.timestamps     end   end

  def self.down     drop_table :models   end end

Now, if I need the same fields in another table, I need to put again :

. . t.string :description, :default => "short Description", :limit => 20 t.string :longdescription, :default => "long Description", :limit => 40 . .

How can I create something like a "template" or "pattern" that includes for example ":default => "short Description", :limit => 20", then I only use this template to create the new table. Something like this :

. . t.Template2 :description, # 'Template2' includes ":default => "short Description", :limit => 20" t.Template3 :longdescription, # 'Template3' includes ":default => "long Description", :limit => 40" . .

Then I will use this new type to create new fields with the same characteristics in all the tables.

Thanks,

Jose.

2

How can I create something like a "template" or "pattern" that
includes for example ":default => "short Description", :limit =>
20", then I only use this template to create the new table.
Something like this :

. . t.Template2 :description, # 'Template2' includes ":default => "short
Description", :limit => 20" t.Template3 :longdescription, # 'Template3' includes ":default =>
"long Description", :limit => 40" . .

Then I will use this new type to create new fields with the same
characteristics in all the tables.

Well you could certainly add methods to the TableDefinition class
(which is the class of the objects yielded by the create_table block)
if you wanted to.

Fred

3

Thanks Fred,

If I have :

class CreateModels < ActiveRecord::Migration   def self.up     create_table :models do |t|       t.Template1 :model,       t.Template2 :description,       t.Template3 :longdescription,

      t.timestamps     end   end

I need to create the method inside "CreateModels" ? or Inside "Models".

And then how can I use this "Template" in another "Table definition".

Thanks.

4

Thanks Fred,

If I have :

class CreateModels < ActiveRecord::Migration def self.up    create_table :models do |t|      t.Template1 :model,      t.Template2 :description,      t.Template3 :longdescription,

     t.timestamps    end end

I need to create the method inside "CreateModels" ? or Inside
"Models".

Neither. I was suggesting extending the TableDefinition (defined in
schema_defintion.rb)

Fred

5

Thanks agai Fred,

If I change the file in rails directory :

Neither. I was suggesting extending the TableDefinition (defined in
schema_defintion.rb)

Then If I upgrade to another rails version I need to modify the file again ?

Exists another way to put it inside the rails application independent from rails upgrade ?

Thanks,

Jose.

6

Thanks agai Fred,

If I change the file in rails directory :

> Neither. I was suggesting extending the TableDefinition > (defined in
> schema_defintion.rb)

I wouldn't do that. This is ruby - you can reopen a class whenever you feel like it, eg stick it in a file in lib and require that or (if you're going to reuse it across apps) make it into a plugin.

Fred

7

Thanks Fred,

I will try with two of them.

About Plugins i found :

http://nubyonrails.com/articles/2006/05/04/the-complete-guide-to-rails-plugins-part-i http://nubyonrails.com/articles/2006/05/09/the-complete-guide-to-rails-plugins-part-ii

But, about libraries inside rails ..., do you know some places that i could read ?

Thanks

Jose.