aboutsummaryrefslogtreecommitdiffstats
path: root/activerecord/lib/active_record/associations/through_association.rb
blob: 65ca4b1282b17a2fce64c0b390d3b40433c84812 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
module ActiveRecord
  # = Active Record Through Association
  module Associations
    module ThroughAssociation

      def scoped
        with_scope(@scope) do
          @reflection.klass.scoped &
          @reflection.through_reflection.klass.scoped
        end
      end

      def stale_target?
        if @target && @reflection.through_reflection.macro == :belongs_to && defined?(@through_foreign_key)
          previous_key = @through_foreign_key.to_s
          current_key  = @owner.send(@reflection.through_reflection.primary_key_name).to_s

          previous_key != current_key
        else
          false
        end
      end

      protected

      def construct_find_scope
        {
          :conditions => construct_conditions,
          :joins      => construct_joins,
          :include    => @reflection.options[:include] || @reflection.source_reflection.options[:include],
          :select     => construct_select,
          :order      => @reflection.options[:order],
          :limit      => @reflection.options[:limit],
          :readonly   => @reflection.options[:readonly]
        }
      end

      # This scope affects the creation of the associated records (not the join records). At the
      # moment we only support creating on a :through association when the source reflection is a
      # belongs_to. Thus it's not necessary to set a foreign key on the associated record(s), so
      # this scope has can legitimately be empty.
      def construct_create_scope
        { }
      end

      def aliased_through_table
        name = @reflection.through_reflection.table_name

        @reflection.table_name == name ?
          @reflection.through_reflection.klass.arel_table.alias(name + "_join") :
          @reflection.through_reflection.klass.arel_table
      end

      def construct_owner_conditions
        super(aliased_through_table, @reflection.through_reflection)
      end

      def construct_select
        @reflection.options[:select] ||
        @reflection.options[:uniq] && "DISTINCT #{@reflection.quoted_table_name}.*"
      end

      def construct_joins
        right = aliased_through_table
        left  = @reflection.klass.arel_table

        conditions = []

        if @reflection.source_reflection.macro == :belongs_to
          reflection_primary_key = @reflection.source_reflection.options[:primary_key] ||
                                   @reflection.klass.primary_key
          source_primary_key     = @reflection.source_reflection.primary_key_name
          if @reflection.options[:source_type]
            column = @reflection.source_reflection.options[:foreign_type]
            conditions <<
              right[column].eq(@reflection.options[:source_type])
          end
        else
          reflection_primary_key = @reflection.source_reflection.primary_key_name
          source_primary_key     = @reflection.source_reflection.options[:primary_key] ||
                                   @reflection.through_reflection.klass.primary_key
          if @reflection.source_reflection.options[:as]
            column = "#{@reflection.source_reflection.options[:as]}_type"
            conditions <<
              left[column].eq(@reflection.through_reflection.klass.name)
          end
        end

        conditions <<
          left[reflection_primary_key].eq(right[source_primary_key])

        right.create_join(
          right,
          right.create_on(right.create_and(conditions)))
      end

      # Construct attributes for :through pointing to owner and associate.
      def construct_join_attributes(associate)
        # TODO: revisit this to allow it for deletion, supposing dependent option is supported
        raise ActiveRecord::HasManyThroughCantAssociateThroughHasOneOrManyReflection.new(@owner, @reflection) if [:has_one, :has_many].include?(@reflection.source_reflection.macro)

        join_attributes = {
          @reflection.source_reflection.primary_key_name =>
            associate.send(@reflection.source_reflection.association_primary_key)
        }

        if @reflection.options[:source_type]
          join_attributes.merge!(@reflection.source_reflection.options[:foreign_type] => associate.class.base_class.name)
        end

        if @reflection.through_reflection.options[:conditions].is_a?(Hash)
          join_attributes.merge!(@reflection.through_reflection.options[:conditions])
        end

        join_attributes
      end

      def conditions
        @conditions = build_conditions unless defined?(@conditions)
        @conditions
      end

      def build_conditions
        association_conditions = @reflection.options[:conditions]
        through_conditions = build_through_conditions
        source_conditions = @reflection.source_reflection.options[:conditions]
        uses_sti = !@reflection.through_reflection.klass.descends_from_active_record?

        if association_conditions || through_conditions || source_conditions || uses_sti
          all = []

          [association_conditions, source_conditions].each do |conditions|
            all << interpolate_sql(sanitize_sql(conditions)) if conditions
          end

          all << through_conditions  if through_conditions
          all << build_sti_condition if uses_sti

          all.map { |sql| "(#{sql})" } * ' AND '
        end
      end

      def build_through_conditions
        conditions = @reflection.through_reflection.options[:conditions]
        if conditions.is_a?(Hash)
          interpolate_sql(@reflection.through_reflection.klass.send(:sanitize_sql, conditions)).gsub(
            @reflection.quoted_table_name,
            @reflection.through_reflection.quoted_table_name)
        elsif conditions
          interpolate_sql(sanitize_sql(conditions))
        end
      end

      def build_sti_condition
        @reflection.through_reflection.klass.send(:type_condition).to_sql
      end

      alias_method :sql_conditions, :conditions

      def update_stale_state
        if @reflection.through_reflection.macro == :belongs_to
          @through_foreign_key = @owner.send(@reflection.through_reflection.primary_key_name)
        end
      end
    end
  end
end