Module: Rankable::Model::ClassMethods

Defined in:
lib/rankable/model.rb

Instance Method Summary collapse

Instance Method Details

#rank_all(ids) ⇒ Object

Ranks all records by given IDs. Example:

Article.rank_all([7,5,3])
Article.find(7).rank # => 1
Article.find(5).rank # => 2
Article.find(3).rank # => 3

Works with scopes too. Example:

Article.unread.rank_all([2,4,3])



30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
 
# File 'lib/rankable/model.rb', line 30

def rank_all(ids)
  pk_col = columns_hash[primary_key]
  rk_col = columns_hash[rankable_column_name.to_s]

  raise "Ranking only works with integer primary keys" unless pk_col && pk_col.type == :integer
  raise "Ranking is missing the '#{rankable_column_name}' column. Please add a '#{rankable_column_name}' to your database table or specify a custom column name via self.rankable_column_name = '...'" unless rk_col

  ranked = Array.wrap(ids).map do |value|
    Integer(value) rescue nil
  end.compact
  return 0 if ranked.empty?

  clause = ranked.each_with_index.map do |id, index|
    "WHEN #{connection.quote(id, pk_col)} THEN #{connection.quote(index + 1, rk_col)}"
  end.join(' ')

  where(primary_key.to_sym => ranked).update_all "#{connection.quote_column_name rankable_column_name} = CASE #{quoted_primary_key} #{clause} END"
end