On 5 June 2011 10:15, Colin Law <[email protected]> wrote: > I have never used the for_charity? syntax though. There does not seem > much point when it is a boolean.
I've been using it ever since reading dire warnings in the first edition of Agile Web Development with Rails: "[To represent true or false, some databases] use integer columns, where 0 is false and 1 is true... The problem is that in Ruby the number 0 and the string "f" are both interpreted as true values in conditions... To query a column as a boolean value in a condition, you must append a question mark to the column's name" I must confess I was surprised to learn (prompted by this thread) that Active Record has a feature that emulates boolean columns for databases that don't support them natively, so you do get a literal true or false value out of the attribute, instead of a 1 or 0. And was even more surprised to learn that this feature was added quite a long time ago (version 1-ish, AFAICT). But warnings like the above are still passed on (and in fact are still present in the current edition of AWDWR). I and others clearly missed the memo. > Is that syntax documented somewhere? It's currently implemented in ActiveRecord::AttributeMethods::Query, and mentioned in the preamble doc for ActiveRecord::Base (but only as a way of checking for the presence of attributes, not as a way to typecast fake boolean columns). The MySQL connection adaptor's boolean emulation behaviour is configurable via ActiveRecord::ConnectionAdapters::MysqlAdapter.emulate_booleans, which is documented. Chris -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
