InfoQ Article: DrySQL ORM for Rails

Posted by Obie Fernandez on Dec 14, 2006

Sections

Development,

Architecture & Design

Topics

Ruby ,

Programming ,

Ruby on Rails

Tags

ActiveRecord ,

DrySQL ,

ORM

Bryan Evans of the DrySQL project felt that ActiveRecord falls a bit short of complying with the DRY principle. If you have tables or columns that aren't compatible with the naming conventions, then you need to redefine some of your database artifacts in application code. As well, ActiveRecord associations and validations are redundant specifications of database constraints. Bryan wants to be able to change his database schema without needing to re-wire the ORM layer(s) of dependent applications. He wants to avoid (as much as possible) the situation where he's averse to making a change to his database schema because of the effort that would be required to sync up dependent applications.

Since ActiveRecord uses the database's information schema to dynamically retrieve column metadata, Bryan asked: "Can this strategy be applied to all database artifacts?"

Read ORM with DrySQL and ActiveRecord

1. Back to top

   Clarification

   by Bryan Evans

   I should have been more careful in my description of validates_nullability_of. To clarify, this validation always rejects a null value, but the validation is only generated by DrySQL in situations where the DB would reject a null.

   Reply

2. Back to top

   Re: Clarification

   by Sam Smoot

   It might be interesting to see this work contrasted with Dr. Nic's "Magic Models" (magicmodels.rubyforge.org/).
   
   I haven't used either, but they seem to share some goals, so maybe a collaborative effort would be beneficial?

   Reply

3. Back to top

   Typos in code snippet #1

   by Tyler Rick

   This code snippet has the line:
   
   Employee bryan = Employees.find(18)
   
   1. The 'Employee' before bryan is unneeded and incorrect. (Might be correct in a *statically* typed language like Java where you actually have to declare variables... :) )
   
   2. Model names are singular: Employee.find(18)

   Reply

• Older >