From: "J. Ryan Sobol" <ryansobol@...>
Date: 2005-12-26T13:10:30+09:00
Subject: Re: Where is the attribute definition of Category class?


On Dec 25, 2005, at 6:49 PM, Sadys HumbleBee wrote:

> Thanks, ryan. I'v joined the rails mailing list now, ...

Good work! :-D

> but I think as we going on, this problem is becoming more like a  
> ruby problem,~!~

Nuts.

> I think if there is any compile tool in ruby that is powerful  
> enough to check the reference to my class and the database  
> structure to determine if the references are valid,

We are still talking about Rails, right?  ActiveRecord determines the  
columns in a database table dynamically at runtime.  In other words,  
Rails doesn't check the 'references' to the table, it *creates*  
them.  Here an example SQL table definition and an associated  
ActiveRecord sub-class definition.

create table friends (
	id		int 				not null auto_increment,
	name	varchar(100)		not null
);

class Friend < ActiveRecord::Base
end

Now, by running the code

friend = Friend.new
friend.name = 'Foo'

Rails automatically adds the following method the Friend class

def name=(value)
	@name = value
end

and then sends a message to that method with the  'Foo' argument.   
This all happens because Friend is a sub-class of ActiveRecord (and  
because you told your Rails app how to find the friend table via the  
databases.yml file too).

> or if there is any unit test automatation tool which can generate  
> cases for that purpose.

Unit testing is an important part of Rails apps, but I'd suggest  
diving right into Rails development before you think about testing.

>
> Code convertion is a way, but only suitable for experienced  
> programmer.  And the defer of the attribute definition will cause  
> some word-complete function not work, such as that in source insight.

I'm not really sure what you meant by these statements.

> And is it dangerous if I supply a library that any user  can fill  
> any attributes into it  by using method_missing? A library must be  
> able to deal with any misuage or malicious attack. Safety  
> guaranteed by documentation is not really safe.

ActiveRecord, like most classes, *does* in fact deal with sending  
messages to non-existent methods:  It throws an exception.  :)

I'm not entirely sure what you're driving at, but if you haven't done  
any Rails programming I'd suggest you start with a few tutorials  
online.  If you're still intrigued by Rails and the Ruby language,  
there are some great books over at http:// 
www.pragmaticprogrammers.com that I personally recommend.

Good luck!

~ ryan ~