Class: ActiveRecord::Result

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/active_record/result.rb

Overview

This class encapsulates a result returned from calling #exec_query on any database connection adapter. For example:

result = ActiveRecord::Base.connection.exec_query('SELECT id, title, body FROM posts')
result # => #<ActiveRecord::Result:0xdeadbeef>

# Get the column names of the result:
result.columns
# => ["id", "title", "body"]

# Get the record values of the result:
result.rows
# => [[1, "title_1", "body_1"],
      [2, "title_2", "body_2"],
      ...
     ]

# Get an array of hashes representing the result (column => value):
result.to_a
# => [{"id" => 1, "title" => "title_1", "body" => "body_1"},
      {"id" => 2, "title" => "title_2", "body" => "body_2"},
      ...
     ]

# ActiveRecord::Result also includes Enumerable.
result.each do |row|
  puts row['title'] + " " + row['body']
end

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(columns, rows, column_types = {}) ⇒ Result

Returns a new instance of Result.



43
44
45
46
47
48
 
# File 'lib/active_record/result.rb', line 43

def initialize(columns, rows, column_types = {})
  @columns      = columns
  @rows         = rows
  @hash_rows    = nil
  @column_types = column_types
end

Instance Attribute Details

#column_types ⇒ Object (readonly)

Returns the value of attribute column_types.



37
38
39
 
# File 'lib/active_record/result.rb', line 37

def column_types
  @column_types
end

#columns ⇒ Object (readonly)

Returns the value of attribute columns.



37
38
39
 
# File 'lib/active_record/result.rb', line 37

def columns
  @columns
end

#rows ⇒ Object (readonly)

Returns the value of attribute rows.



37
38
39
 
# File 'lib/active_record/result.rb', line 37

def rows
  @rows
end

Class Method Details

.empty ⇒ Object

:nodoc:



39
40
41
 
# File 'lib/active_record/result.rb', line 39

def self.empty # :nodoc:
  EMPTY
end

Instance Method Details

#[](idx) ⇒ Object 



87
88
89
 
# File 'lib/active_record/result.rb', line 87

def [](idx)
  hash_rows[idx]
end

#cancel ⇒ Object

:nodoc:



100
101
102
 
# File 'lib/active_record/result.rb', line 100

def cancel # :nodoc:
  self
end

#cast_values(type_overrides = {}) ⇒ Object

:nodoc:



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
 
# File 'lib/active_record/result.rb', line 104

def cast_values(type_overrides = {}) # :nodoc:
  if columns.one?
    # Separated to avoid allocating an array per row

    type = if type_overrides.is_a?(Array)
      type_overrides.first
    else
      column_type(columns.first, 0, type_overrides)
    end

    rows.map do |(value)|
      type.deserialize(value)
    end
  else
    types = if type_overrides.is_a?(Array)
      type_overrides
    else
      columns.map.with_index { |name, i| column_type(name, i, type_overrides) }
    end

    rows.map do |values|
      Array.new(values.size) { |i| types[i].deserialize(values[i]) }
    end
  end
end

#each(&block) ⇒ Object

Calls the given block once for each element in row collection, passing row as parameter.

Returns an Enumerator if no block is given.



67
68
69
70
71
72
73
 
# File 'lib/active_record/result.rb', line 67

def each(&block)
  if block_given?
    hash_rows.each(&block)
  else
    hash_rows.to_enum { @rows.size }
  end
end

#empty? ⇒ Boolean

Returns true if there are no records, otherwise false.

Returns:

  • (Boolean) 


76
77
78
 
# File 'lib/active_record/result.rb', line 76

def empty?
  rows.empty?
end

#includes_column?(name) ⇒ Boolean

Returns true if this result set includes the column named name

Returns:

  • (Boolean) 


54
55
56
 
# File 'lib/active_record/result.rb', line 54

def includes_column?(name)
  @columns.include? name
end

#initialize_copy(other) ⇒ Object 



130
131
132
133
134
135
 
# File 'lib/active_record/result.rb', line 130

def initialize_copy(other)
  @columns      = columns.dup
  @rows         = rows.dup
  @column_types = column_types.dup
  @hash_rows    = nil
end

#last(n = nil) ⇒ Object

Returns the last record from the rows collection.



92
93
94
 
# File 'lib/active_record/result.rb', line 92

def last(n = nil)
  n ? hash_rows.last(n) : hash_rows.last
end

#length ⇒ Object

Returns the number of elements in the rows array.



59
60
61
 
# File 'lib/active_record/result.rb', line 59

def length
  @rows.length
end

#result ⇒ Object

:nodoc:



96
97
98
 
# File 'lib/active_record/result.rb', line 96

def result # :nodoc:
  self
end

#to_ary ⇒ Object Also known as: to_a

Returns an array of hashes representing each row record.



81
82
83
 
# File 'lib/active_record/result.rb', line 81

def to_ary
  hash_rows
end