[Rails] Active Record Question

[Aled Davies]

(I posted this at ruby-forum, but I figured that I should also try 
here):

I'm new to Ruby and Rails and am evaluating using Ruby on Rails as the 
framework for an asset management project I'm working on and have run 
into an issue with Active Record that I'm wondering if there is anyway 
around.

The issue is this, one of the requirements I have is that all asset 
primary keys must be UUIDs. MySQL 4.1 allows the generation of UUIDs 
using 'SELECT UUID()' so to implement support for using a UUID as a 
primary key, I added the following methods to my model class:

Code:

   def uuid()
      sql = "SELECT UUID()"   
      record = connection.select_one(sql, " #{name} UUID generated")
      return record['UUID()']
   end
   
   # Override create to insert the identifier prior to creation.
   def create
      self.id = uuid();
      super
   end      

As this code will be common to all models in the application I figured 
that I could move this into a super-class (that extends 
ActiveRecord::Base) that sub-classes can extend to get this 
functionality for free. The problem is that ActiveRecord tries apply 
the single-table inheritance rule to the model and tries to insert a 
type in the table (which fails because it isn't in the model).

And so the question is this. Is there anyway of having a custom 
super-class for your models which won't trigger the single-table 
inheritance rule ?

(while I realize that I can just add a 'type' field to the database, it 
seems like the wrong thing to have to do in this case. I also tried 
using a Module, but this seemed not to work, but I suspect that was 
down to my newness with Ruby)

	Thanks

	Aled


--
Aled Davies <awd at well.com>
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