tags:

views:

334

answers:

2
Q: 

Find Methods in derived classes with ActiveRecord - Single Table Inheritance

Hello,

I have a class that derives from ActiveRecord::Base. This class has a subclass that is differentiated in the database by a type id column. How do I make sure that all the inherited active record functions in the derived classes append the type_id column to the conditions hash on any queries that are executed by the derived class? Are there any kind of "before" functions that I could override to inject a condition into the process for the derived classes?

Thanks!

+3  A: 

If your column was called "type", ActiveRecord would do this automatically for you.

Ryan Bigg  2009-02-26 22:13:53
Thanks - this works great when I changed to a column called type. ActiveRecord puts the name of the model into the type column for each object.
Mattew  2009-02-26 23:02:07
If you don't wish to change the column name then you can also use the set_inheritance_column declaration
Steve Weet  2009-02-27 08:45:32
+1  A: 

What you are doing is called Single Table Inheritance (STI). That's why what Radar said about your column being called type works.

srboisvert  2009-02-27 08:41:21

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