Module: Believer::Relation::ClassMethods

Defined in:
lib/believer/relation.rb

Instance Method Summary collapse

Instance Method Details

#cql_record_relations ⇒ Object 



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# File 'lib/believer/relation.rb', line 6

def cql_record_relations
  @cql_record_relations ||= {}
end

#has_a_relation(name, opts = {}) ⇒ Object

Defines a (one to many) relation.

Parameters:

  • name (Symbol) —

    the name of the relation, which will also be used as an accessor method

  • opts (Hash) (defaults to: {}) —

    the options

Options Hash (opts):

  • :class (Object) —

    the name of the referenced class. If nil, it will be created from the relation name. Can be a constant or a String

  • :foreign_key (Object) —

    the name of the attribute of the referenced class which acts as the key to this object

  • :key (Object) —

    the name of the attribute of the referencing class which acts as the key the referenced records

  • :filter (Object) —

    a Proc or lambda which is called with a Believer::Query instance as a parameter to tweak the relation query



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# File 'lib/believer/relation.rb', line 38

def has_a_relation(name, opts = {})
  defaults = {
  }
  options = defaults.merge(opts)

  # Use a proc to avoid classes not yet loaded being referenced
  get_relation_class = lambda do
    if options[:relation_class].nil?
      relation_class = options[:class]
      if relation_class.nil?
        cn = name.to_s.camelize
        if options[:type] == :one_2_many
          cn = cn[0, (name.to_s.size - 1)]
        end
        relation_class = Kernel.const_get(cn)
      elsif relation_class.is_a?(String)
        relation_class = relation_class.split('::').inject(Kernel) { |scope, const_name| scope.const_get(const_name) }
      end
      options[:relation_class] = relation_class
    end
    options[:relation_class]
  end

  cql_record_relations[name] = options

  opts[:foreign_key] = opts[:foreign_key].is_a?(Array) ? opts[:foreign_key] : [opts[:foreign_key]]
  opts[:key] = opts[:key].is_a?(Array) ? opts[:key] : [opts[:key]]

  raise "key and foreign_key must have same number of items" if opts[:key].size != opts[:foreign_key].size

  self.redefine_method(name) do |reload = false|
    relation_class = get_relation_class.call

    q = relation_class.scoped
    opts[:foreign_key].each_with_index do |fk, index|
      key = opts[:key][index]
      q = q.where(fk => self.send(key))
    end
    if options[:filter]
      q = self.instance_exec(q, &(options[:filter]))
      unless q
        er = EmptyResult.new(:record_class => relation_class)
        er.extend(CollectionMethods)
        er.extend(::Believer::FinderMethods)
        return er
      end
    end
    return q.first if options[:type] == :one_2_one

    col = Collection.new(q.query_attributes)
    col.to_a if reload
    col
  end

end

#has_single(name, opts = {}) ⇒ Object 



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# File 'lib/believer/relation.rb', line 10

def has_single(name, opts = {})
  if opts[:foreign_key].nil?
    opts[:foreign_key] = opts[:key].nil? ? :id : opts[:key]
  end
  if opts[:key].nil?
    opts[:key] = opts[:foreign_key].nil? ? "#{self.name.underscore}_id".to_sym : opts[:foreign_key]
  end
  has_a_relation(name, opts.merge(:type => :one_2_one))
end

#has_some(name, opts = {}) ⇒ Object 



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# File 'lib/believer/relation.rb', line 20

def has_some(name, opts = {})
  if opts[:foreign_key].nil?
    opts[:foreign_key] = opts[:key].nil? ? "#{self.name.underscore}_id".to_sym : opts[:key]
  end
  if opts[:key].nil?
    opts[:key] = opts[:foreign_key].nil? ? :id : opts[:foreign_key]
  end

  has_a_relation(name, opts.merge(:type => :one_2_many))
end