Question

Piggy backing off another question I posted, I have a complex find() that changes whether or not a certain id is nil or not. See here:

if self.id.nil?
  blocks = AppointmentBlock.find(:first,
    :conditions => ['appointment_blocks.employee_id = ? and ' +
                    '(time_slots.start_at between ? and ? or time_slots.end_at between ? and ?)',
    self.employee_id, self.time_slot.start_at, self.time_slot.end_at,
    self.time_slot.start_at, self.time_slot.end_at],
    :joins => 'join time_slots on time_slots.time_slot_role_id = appointment_blocks.id')
else
  blocks = AppointmentBlock.find(:first,
    :conditions => ['appointment_blocks.id != ? and ' +
                    'appointment_blocks.employee_id = ? and ' +
                    '(time_slots.start_at between ? and ? or time_slots.end_at between ? and ?)',
    self.id, self.employee_id, self.time_slot.start_at, self.time_slot.end_at,
    self.time_slot.start_at, self.time_slot.end_at],
    :joins => 'join time_slots on time_slots.time_slot_role_id = appointment_blocks.id')
end

I’m wondering if there is a gem out there that lets me pass in :first and :conditions type stuff as a block of code. I saw ez_where on github but wasn’t sure if it was abandoned or not since its had no activity lately (although that could mean its very solid with no bugs) Any ideas?

Answer 1

You can also have a look at Arel which:

Arel is a Relational Algebra for Ruby.
It 1) simplifies the generation
complex of SQL queries

The approach is built into Rails 3 as well. Provides really elegant support for building complex chains of scopes and queries.