I'd be interested in the author's take on ActiveRecord's implementation of Relational Algebra with ARel[1]:
> To manipulate a SQL query we must manipulate a string. There is a string algebra, but its operations are things like substring, concatenation, substitution, and so forth–not so useful. In the Relational Algebra, there are no queries per se; everything is either a relation or an operation on a relation. Connect the dots and with the algebra we get something like “everything is named_scope” for free.
Also, if I couldn't use something like ActiveRecord in my Rails apps, I'd end up re-writing most of its functionality in my model code somewhere. If I don't get Model#find_by_some_attribute() for free, then I have to spend time writing it.
> To manipulate a SQL query we must manipulate a string. There is a string algebra, but its operations are things like substring, concatenation, substitution, and so forth–not so useful. In the Relational Algebra, there are no queries per se; everything is either a relation or an operation on a relation. Connect the dots and with the algebra we get something like “everything is named_scope” for free.
Also, if I couldn't use something like ActiveRecord in my Rails apps, I'd end up re-writing most of its functionality in my model code somewhere. If I don't get Model#find_by_some_attribute() for free, then I have to spend time writing it.
[1] http://magicscalingsprinkles.wordpress.com/2010/01/28/why-i-...