build_from_hash

# File activerecord/lib/active_record/relation/predicate_builder.rb, line 20
    def self.build_from_hash(klass, attributes, default_table)
      queries = []

      attributes.each do |column, value|
        table = default_table

        if value.is_a?(Hash)
          if value.empty?
            queries << '1=0'
          else
            table       = Arel::Table.new(column, default_table.engine)
            association = klass._reflect_on_association(column)

            value.each do |k, v|
              queries.concat expand(association && association.klass, table, k, v)
            end
          end
        else
          column = column.to_s

          if column.include?('.')
            table_name, column = column.split('.', 2)
            table = Arel::Table.new(table_name, default_table.engine)
          end

          queries.concat expand(klass, table, column, value)
        end
      end

      queries
    end