Class: ActiveRecord::Associations::JoinDependency::JoinAssociation

Inherits:
JoinPart
  • Object
show all
Defined in:
lib/active_record/associations/join_dependency/join_association.rb

Overview

:nodoc:

Defined Under Namespace

Classes: JoinInformation

Instance Attribute Summary collapse

Attributes inherited from JoinPart

#base_klass, #children

Instance Method Summary collapse

Methods inherited from JoinPart

#each, #extract_record, #instantiate, #name

Constructor Details

#initialize(reflection, children) ⇒ JoinAssociation

Returns a new instance of JoinAssociation.



12
13
14
15
16
17
 
# File 'lib/active_record/associations/join_dependency/join_association.rb', line 12

def initialize(reflection, children)
  super(reflection.klass, children)

  @reflection      = reflection
  @tables          = nil
end

Instance Attribute Details

#reflection ⇒ Object (readonly)

The reflection of the association represented



8
9
10
 
# File 'lib/active_record/associations/join_dependency/join_association.rb', line 8

def reflection
  @reflection
end

#tables ⇒ Object

Returns the value of attribute tables.



10
11
12
 
# File 'lib/active_record/associations/join_dependency/join_association.rb', line 10

def tables
  @tables
end

Instance Method Details

#aliased_table_name ⇒ Object 



122
123
124
 
# File 'lib/active_record/associations/join_dependency/join_association.rb', line 122

def aliased_table_name
  table.table_alias || table.name
end

#build_constraint(klass, table, key, foreign_table, foreign_key) ⇒ Object

Builds equality condition.

Example:

class Physician < ActiveRecord::Base
  has_many :appointments
end

If I execute `Physician.joins(:appointments).to_a` then
  klass         # => Physician
  table         # => #<Arel::Table @name="appointments" ...>
  key           # =>  physician_id
  foreign_table # => #<Arel::Table @name="physicians" ...>
  foreign_key   # => id



105
106
107
108
109
110
111
112
113
114
115
116
 
# File 'lib/active_record/associations/join_dependency/join_association.rb', line 105

def build_constraint(klass, table, key, foreign_table, foreign_key)
  constraint = table[key].eq(foreign_table[foreign_key])

  if klass.finder_needs_type_condition?
    constraint = table.create_and([
      constraint,
      klass.send(:type_condition, table)
    ])
  end

  constraint
end

#join_constraints(foreign_table, foreign_klass, node, join_type, tables, scope_chain, chain) ⇒ Object 



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
 
# File 'lib/active_record/associations/join_dependency/join_association.rb', line 26

def join_constraints(foreign_table, foreign_klass, node, join_type, tables, scope_chain, chain)
  joins         = []
  bind_values   = []
  tables        = tables.reverse

  scope_chain_index = 0
  scope_chain = scope_chain.reverse

  # The chain starts with the target table, but we want to end with it here (makes
  # more sense in this context), so we reverse
  chain.reverse_each do |reflection|
    table = tables.shift
    klass = reflection.klass

    join_keys   = reflection.join_keys(klass)
    key         = join_keys.key
    foreign_key = join_keys.foreign_key

    constraint = build_constraint(klass, table, key, foreign_table, foreign_key)

    scope_chain_items = scope_chain[scope_chain_index].map do |item|
      if item.is_a?(Relation)
        item
      else
        ActiveRecord::Relation.create(klass, table).instance_exec(node, &item)
      end
    end
    scope_chain_index += 1

    klass_scope =
      if klass.current_scope && klass.current_scope.values.blank?
        klass.unscoped
      else
        klass.send(:build_default_scope, ActiveRecord::Relation.create(klass, table))
      end
    scope_chain_items.concat [klass_scope].compact

    rel = scope_chain_items.inject(scope_chain_items.shift) do |left, right|
      left.merge right
    end

    if rel && !rel.arel.constraints.empty?
      bind_values.concat rel.bind_values
      constraint = constraint.and rel.arel.constraints
    end

    if reflection.type
      value = foreign_klass.base_class.name
      column = klass.columns_hash[reflection.type.to_s]

      substitute = klass.connection.substitute_at(column)
      bind_values.push [column, value]
      constraint = constraint.and table[reflection.type].eq substitute
    end

    joins << table.create_join(table, table.create_on(constraint), join_type)

    # The current table in this iteration becomes the foreign table in the next
    foreign_table, foreign_klass = table, klass
  end

  JoinInformation.new joins, bind_values
end

#match?(other) ⇒ Boolean

Returns:

  • (Boolean) 


19
20
21
22
 
# File 'lib/active_record/associations/join_dependency/join_association.rb', line 19

def match?(other)
  return true if self == other
  super && reflection == other.reflection
end

#table ⇒ Object 



118
119
120
 
# File 'lib/active_record/associations/join_dependency/join_association.rb', line 118

def table
  tables.first
end