Module: Squeel::Adapters::ActiveRecord::Relation

Defined in:
lib/squeel/adapters/active_record/relation.rb,
lib/squeel/adapters/active_record/3.0/relation.rb

Constant Summary collapse

JoinAssociation = 
::ActiveRecord::Associations::ClassMethods::JoinDependency::JoinAssociation
JoinDependency = 
::ActiveRecord::Associations::ClassMethods::JoinDependency

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#join_dependency ⇒ Object

Returns a JoinDependency for the current relation.

We don’t need to clear out @join_dependency by overriding #reset, because the default #reset already does this, despite never setting it anywhere that I can find. Serendipity, I say!



19
20
21
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 19

def join_dependency
  @join_dependency ||= (build_join_dependency(table.from(table), @joins_values) && @join_dependency)
end

Class Method Details

.included(base) ⇒ Object

ZOMG ALIAS_METHOD_CHAIN IS BELOW. HIDE YOUR EYES! … … … Since you’re still looking, let me explain this horrible transgression you see before you. You see, Relation#where_values_hash is defined on the ActiveRecord::Relation class. Since it’s defined there, but I would very much like to modify its behavior, I have three choices.

  1. Inherit from ActiveRecord::Relation in a Squeel::Relation class, and make an attempt to usurp all of the various calls to methods on ActiveRecord::Relation by doing some really evil stuff with constant reassignment, all for the sake of being able to use super().

  2. Submit a patch to Rails core, breaking this method off into another module, all for my own selfish desire to use super() while mucking about in Rails internals.

  3. Use alias_method_chain, and say 10 hail Hanssons as penance.

I opted to go with #3. Except for the hail Hansson thing. Unless you’re DHH, in which case, I totally said them.



336
337
338
339
340
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 336

def self.included(base)
  base.class_eval do
    alias_method_chain :where_values_hash, :squeel
  end
end

Instance Method Details

#attribute_visitor ⇒ Object 



29
30
31
32
33
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 29

def attribute_visitor
  Visitors::AttributeVisitor.new(
    Context.new(join_dependency)
  )
end

#build_arel ⇒ Object 



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
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 73

def build_arel
  arel = table.from table

  build_join_dependency(arel, @joins_values) unless @joins_values.empty?

  predicate_viz = predicate_visitor
  attribute_viz = attribute_visitor

  collapse_wheres(arel, predicate_viz.accept((@where_values - ['']).uniq))

  arel.having(*predicate_viz.accept(@having_values.uniq.reject{|h| h.blank?})) unless @having_values.empty?

  arel.take(connection.sanitize_limit(@limit_value)) if @limit_value
  arel.skip(@offset_value) if @offset_value

  arel.group(*attribute_viz.accept(@group_values.uniq.reject{|g| g.blank?})) unless @group_values.empty?

  order = @reorder_value ? @reorder_value : @order_values
  order = attribute_viz.accept(order.uniq.reject{|o| o.blank?})
  order = reverse_sql_order(sqlify_order(order)) if @reverse_order_value
  arel.order(*order) unless order.empty?

  build_select(arel, attribute_viz.accept(@select_values.uniq))

  arel.from(@from_value) if @from_value
  arel.lock(@lock_value) if @lock_value

  arel
end

#build_join_dependency(relation, joins) ⇒ Object 



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
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 111

def build_join_dependency(manager, joins)
  buckets = joins.group_by do |join|
    case join
    when String
      'string_join'
    when Hash, Symbol, Array, Nodes::Stub, Nodes::Join, Nodes::KeyPath
      'association_join'
    when JoinAssociation
      'stashed_join'
    when Arel::Nodes::Join
      'join_node'
    else
      raise 'unknown class: %s' % join.class.name
    end
  end

  association_joins         = buckets['association_join'] || []
  stashed_association_joins = buckets['stashed_join'] || []
  join_nodes                = buckets['join_node'] || []
  string_joins              = (buckets['string_join'] || []).map { |x|
    x.strip
  }.uniq

  join_list = custom_join_ast(manager, string_joins)

  # All of this duplication just to add
  self.join_dependency = JoinDependency.new(
    @klass,
    association_joins,
    join_list
  )

  join_nodes.each do |join|
    join_dependency.alias_tracker.aliased_name_for(join.left.name.downcase)
  end

  join_dependency.graft(*stashed_association_joins)

  @implicit_readonly = true unless association_joins.empty? && stashed_association_joins.empty?

  join_dependency.join_associations.each do |association|
    association.join_to(manager)
  end

  manager.join_sources.concat join_nodes.uniq
  manager.join_sources.concat join_list

  manager
end

#build_where(opts, other = []) ⇒ Object 



247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 247

def build_where(opts, other = [])
  case opts
  when String, Array
    super
  else  # Let's prevent PredicateBuilder from doing its thing
    [opts, *other].map do |arg|
      case arg
      when Array  # Just in case there's an array in there somewhere
        @klass.send(:sanitize_sql, arg)
      when Hash
        @klass.send(:expand_hash_conditions_for_aggregates, arg)
      else
        arg
      end
    end
  end
end

#collapse_wheres(arel, wheres) ⇒ Object 



265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 265

def collapse_wheres(arel, wheres)
  wheres = [wheres] unless Array === wheres
  binaries = wheres.grep(Arel::Nodes::Binary)

  groups = binaries.group_by {|b| [b.class, b.left]}

  groups.each do |_, bins|
    arel.where(Arel::Nodes::And.new(bins))
  end

  (wheres - binaries).each do |where|
    where = Arel.sql(where) if String === where
    arel.where(Arel::Nodes::Grouping.new(where))
  end
end

#debug_sql ⇒ Object

Simulate the logic that occurs in #to_a

This will let us get a dump of the SQL that will be run against the DB for debug purposes without actually running the query.



300
301
302
303
304
305
306
307
308
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 300

def debug_sql
  if eager_loading?
    including = (@eager_load_values + @includes_values).uniq
    join_dependency = JoinDependency.new(@klass, including, [])
    construct_relation_for_association_find(join_dependency).to_sql
  else
    arel.to_sql
  end
end

#eager_load(*args) ⇒ Object 



177
178
179
180
181
182
183
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 177

def eager_load(*args)
  if block_given? && args.empty?
    super(DSL.eval &Proc.new)
  else
    super
  end
end

#find_equality_predicates(nodes) ⇒ Object 



281
282
283
284
285
286
287
288
289
290
291
292
293
294
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 281

def find_equality_predicates(nodes)
  nodes.map { |node|
    case node
    when Arel::Nodes::Equality
      node if node.left.relation.name == table_name
    when Arel::Nodes::Grouping
      find_equality_predicates([node.expr])
    when Arel::Nodes::And
      find_equality_predicates(node.children)
    else
      nil
    end
  }.compact.flatten
end

#group(*args) ⇒ Object 



199
200
201
202
203
204
205
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 199

def group(*args)
  if block_given? && args.empty?
    super(DSL.eval &Proc.new)
  else
    super
  end
end

#having(*args) ⇒ Object 



239
240
241
242
243
244
245
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 239

def having(*args)
  if block_given? && args.empty?
    super(DSL.eval &Proc.new)
  else
    super
  end
end

#includes(*args) ⇒ Object 



161
162
163
164
165
166
167
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 161

def includes(*args)
  if block_given? && args.empty?
    super(DSL.eval &Proc.new)
  else
    super
  end
end

#infer_association_for_relation_merge(r) ⇒ Object 



58
59
60
61
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 58

def infer_association_for_relation_merge(r)
  default_association = reflect_on_all_associations.detect {|a| a.class_name == r.klass.name}
  default_association ? default_association.name : r.table_name.to_sym
end

#joins(*args) ⇒ Object 



223
224
225
226
227
228
229
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 223

def joins(*args)
  if block_given? && args.empty?
    super(DSL.eval &Proc.new)
  else
    super
  end
end

#merge(r, association_name = nil) ⇒ Object

We need to be able to support merging two relations that have a different base class. Stock ActiveRecord doesn’t have to do anything too special, because it’s already created predicates out of the where_values by now, and they’re already bound to the proper table.

Squeel, on the other hand, needs to do its best to ensure the predicates are still winding up against the proper table. Merging relations is a really nifty shortcut but another little corner of ActiveRecord where the magic quickly fades. :(



43
44
45
46
47
48
49
50
51
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 43

def merge(r, association_name = nil)
  if association_name || relation_with_different_base?(r)
    r = r.clone
    association_name ||= infer_association_for_relation_merge(r)
    prepare_relation_for_association_merge!(r, association_name)
  end

  super(r)
end

#order(*args) ⇒ Object 



207
208
209
210
211
212
213
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 207

def order(*args)
  if block_given? && args.empty?
    super(DSL.eval &Proc.new)
  else
    super
  end
end

#predicate_visitor ⇒ Object 



23
24
25
26
27
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 23

def predicate_visitor
  Visitors::PredicateVisitor.new(
    Context.new(join_dependency)
  )
end

#preload(*args) ⇒ Object 



169
170
171
172
173
174
175
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 169

def preload(*args)
  if block_given? && args.empty?
    super(DSL.eval &Proc.new)
  else
    super
  end
end

#prepare_relation_for_association_merge!(r, association_name) ⇒ Object 



63
64
65
66
67
68
69
70
71
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 63

def prepare_relation_for_association_merge!(r, association_name)
  r.where_values.map! {|w| Squeel::Visitors::PredicateVisitor.can_accept?(w) ? {association_name => w} : w}
  r.having_values.map! {|h| Squeel::Visitors::PredicateVisitor.can_accept?(h) ? {association_name => h} : h}
  r.group_values.map! {|g| Squeel::Visitors::AttributeVisitor.can_accept?(g) ? {association_name => g} : g}
  r.order_values.map! {|o| Squeel::Visitors::AttributeVisitor.can_accept?(o) ? {association_name => o} : o}
  r.select_values.map! {|s| Squeel::Visitors::AttributeVisitor.can_accept?(s) ? {association_name => s} : s}
  r.joins_values.map! {|j| [Symbol, Hash, Nodes::Stub, Nodes::Join, Nodes::KeyPath].include?(j.class) ? {association_name => j} : j}
  r.includes_values.map! {|i| [Symbol, Hash, Nodes::Stub, Nodes::Join, Nodes::KeyPath].include?(i.class) ? {association_name => i} : i}
end

#relation_with_different_base?(r) ⇒ Boolean

Returns:

  • (Boolean) 


53
54
55
56
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 53

def relation_with_different_base?(r)
  ::ActiveRecord::Relation === r &&
  base_class.name != r.klass.base_class.name
end

#reorder(*args) ⇒ Object 



215
216
217
218
219
220
221
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 215

def reorder(*args)
  if block_given? && args.empty?
    super(DSL.eval &Proc.new)
  else
    super
  end
end

#select(value = Proc.new) ⇒ Object 



185
186
187
188
189
190
191
192
193
194
195
196
197
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 185

def select(value = Proc.new)
  if block_given? && Proc === value
    if value.arity > 0
      to_a.select {|*block_args| value.call(*block_args)}
    else
      relation = clone
      relation.select_values += Array.wrap(DSL.eval &value)
      relation
    end
  else
    super
  end
end

#sqlify_order(order) ⇒ Object

reverse_sql_order doesn’t understand ARel ordering nodes, so we need to convert them to their corresponding SQL



105
106
107
108
109
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 105

def sqlify_order(order)
  order.map do |o|
    o.respond_to?(:to_sql) ? o.to_sql : o
  end
end

#where(opts = Proc.new, *rest) ⇒ Object 



231
232
233
234
235
236
237
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 231

def where(opts = Proc.new, *rest)
  if block_given? && Proc === opts
    super(DSL.eval &opts)
  else
    super
  end
end

#where_values_hash_with_squeel ⇒ Object 



342
343
344
345
346
 
# File 'lib/squeel/adapters/active_record/relation.rb', line 342

def where_values_hash_with_squeel
  equalities = find_equality_predicates(predicate_visitor.accept(@where_values))

  Hash[equalities.map { |where| [where.left.name, where.right] }]
end