class Sequel::Plugins::ManyThroughMany::ManyThroughManyAssociationReflection
The AssociationReflection subclass for many_through_many associations.
Public Instance Methods
cloneable?(ref)
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many_through_many and one_through_many associations can be clones
# File lib/sequel/plugins/many_through_many.rb, line 85 def cloneable?(ref) ref[:type] == :many_through_many || ref[:type] == :one_through_many end
default_associated_key_alias()
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The default associated key alias(es) to use when eager loading associations via eager.
# File lib/sequel/plugins/many_through_many.rb, line 91 def default_associated_key_alias self[:uses_left_composite_keys] ? (0...self[:through].first[:left].length).map{|i| :"x_foreign_key_#{i}_x"} : :x_foreign_key_x end
join_table_alias()
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The alias for the first join table.
# File lib/sequel/plugins/many_through_many.rb, line 104 def join_table_alias final_reverse_edge[:alias] end
reciprocal()
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Many through many associations don't have a reciprocal
# File lib/sequel/plugins/many_through_many.rb, line 109 def reciprocal nil end
Private Instance Methods
_associated_dataset()
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# File lib/sequel/plugins/many_through_many.rb, line 115 def _associated_dataset ds = associated_class (reverse_edges + [final_reverse_edge]).each do |t| h = {:qualify=>:deep} if t[:alias] != t[:table] h[:table_alias] = t[:alias] end ds = ds.join(t[:table], Array(t[:left]).zip(Array(t[:right])), h) end ds end
calculate_edges()
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Transform the :through option into a list of edges and reverse edges to use to join tables when loading the association.
# File lib/sequel/plugins/many_through_many.rb, line 145 def calculate_edges es = [{:left_table=>self[:model].table_name, :left_key=>self[:left_primary_key_column]}] self[:through].each do |t| es.last.merge!(:right_key=>t[:left], :right_table=>t[:table], :join_type=>t[:join_type]||self[:graph_join_type], :conditions=>(t[:conditions]||[]).to_a, :block=>t[:block]) es.last[:only_conditions] = t[:only_conditions] if t.include?(:only_conditions) es << {:left_table=>t[:table], :left_key=>t[:right]} end es.last.merge!(:right_key=>right_primary_key, :right_table=>associated_class.table_name) edges = es.map do |e| h = {:table=>e[:right_table], :left=>e[:left_key], :right=>e[:right_key], :conditions=>e[:conditions], :join_type=>e[:join_type], :block=>e[:block]} h[:only_conditions] = e[:only_conditions] if e.include?(:only_conditions) h end reverse_edges = es.reverse.map{|e| {:table=>e[:left_table], :left=>e[:left_key], :right=>e[:right_key]}} reverse_edges.pop calculate_reverse_edge_aliases(reverse_edges) final_reverse_edge = reverse_edges.pop final_reverse_alias = final_reverse_edge[:alias] h = {:final_edge=>edges.pop, :final_reverse_edge=>final_reverse_edge, :edges=>edges, :reverse_edges=>reverse_edges, :predicate_key=>qualify(final_reverse_alias, edges.first[:right]), :associated_key_table=>final_reverse_edge[:alias], } h.each{|k, v| cached_set(k, v)} h end
calculate_reverse_edge_aliases(reverse_edges)
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Make sure to use unique table aliases when lazy loading or eager loading
# File lib/sequel/plugins/many_through_many.rb, line 128 def calculate_reverse_edge_aliases(reverse_edges) aliases = [associated_class.table_name] reverse_edges.each do |e| table_alias = e[:table] if aliases.include?(table_alias) i = 0 table_alias = loop do ta = :"#{table_alias}_#{i}" break ta unless aliases.include?(ta) i += 1 end end aliases.push(e[:alias] = table_alias) end end
filter_by_associations_limit_key()
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# File lib/sequel/plugins/many_through_many.rb, line 175 def filter_by_associations_limit_key fe = edges.first Array(qualify(fe[:table], fe[:right])) + Array(qualify(associated_class.table_name, associated_class.primary_key)) end