Class: ActiveRecord::ConnectionAdapters::Column

Inherits:
Object
  • Object
show all
Defined in:
activerecord/lib/active_record/connection_adapters/column.rb

Overview

An abstract definition of a column in a table.

Defined Under Namespace

Modules: Format

Constant Summary

TRUE_VALUES = 
[true, 1, '1', 't', 'T', 'true', 'TRUE'].to_set
FALSE_VALUES = 
[false, 0, '0', 'f', 'F', 'false', 'FALSE'].to_set

Instance Attribute Summary (collapse)

Class Method Summary (collapse)

Instance Method Summary (collapse)

Constructor Details

- (Column) initialize(name, default, sql_type = nil, null = true)

Instantiates a new column in the table.

name is the column's name, such as supplier_id in supplier_id int(11). default is the type-casted default value, such as new in sales_stage varchar(20) default 'new'. sql_type is used to extract the column's length, if necessary. For example 60 in company_name varchar(60). It will be mapped to one of the standard Rails SQL types in the type attribute. null determines if this column allows NULL values.



29
30
31
32
33
34
35
36
37
38
39
40
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 29

def initialize(name, default, sql_type = nil, null = true)
  @name      = name
  @sql_type  = sql_type
  @null      = null
  @limit     = extract_limit(sql_type)
  @precision = extract_precision(sql_type)
  @scale     = extract_scale(sql_type)
  @type      = simplified_type(sql_type)
  @default   = extract_default(default)
  @primary   = nil
  @coder     = nil
end

Instance Attribute Details

- (Object) coder Also known as: encoded?

Returns the value of attribute coder



17
18
19
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 17

def coder
  @coder
end

- (Object) default (readonly)

Returns the value of attribute default



16
17
18
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 16

def default
  @default
end

- (Object) limit (readonly)

Returns the value of attribute limit



16
17
18
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 16

def limit
  @limit
end

- (Object) name (readonly)

Returns the value of attribute name



16
17
18
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 16

def name
  @name
end

- (Object) null (readonly)

Returns the value of attribute null



16
17
18
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 16

def null
  @null
end

- (Object) precision (readonly)

Returns the value of attribute precision



16
17
18
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 16

def precision
  @precision
end

- (Object) primary

Returns the value of attribute primary



17
18
19
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 17

def primary
  @primary
end

- (Object) scale (readonly)

Returns the value of attribute scale



16
17
18
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 16

def scale
  @scale
end

- (Object) sql_type (readonly)

Returns the value of attribute sql_type



16
17
18
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 16

def sql_type
  @sql_type
end

- (Object) type (readonly)

Returns the value of attribute type



16
17
18
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 16

def type
  @type
end

Class Method Details

+ (Object) binary_to_string(value)

Used to convert from BLOBs to Strings



131
132
133
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 131

def binary_to_string(value)
  value
end

+ (Object) string_to_binary(value)

Used to convert from Strings to BLOBs



126
127
128
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 126

def string_to_binary(value)
  value
end

+ (Object) string_to_date(string) 



135
136
137
138
139
140
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 135

def string_to_date(string)
  return string unless string.is_a?(String)
  return nil if string.empty?

  fast_string_to_date(string) || fallback_string_to_date(string)
end

+ (Object) string_to_dummy_time(string) 



149
150
151
152
153
154
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 149

def string_to_dummy_time(string)
  return string unless string.is_a?(String)
  return nil if string.empty?

  string_to_time "2000-01-01 #{string}"
end

+ (Object) string_to_time(string) 



142
143
144
145
146
147
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 142

def string_to_time(string)
  return string unless string.is_a?(String)
  return nil if string.empty?

  fast_string_to_time(string) || fallback_string_to_time(string)
end

+ (Object) value_to_boolean(value)

convert something to a boolean



157
158
159
160
161
162
163
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 157

def value_to_boolean(value)
  if value.is_a?(String) && value.blank?
    nil
  else
    TRUE_VALUES.include?(value)
  end
end

+ (Object) value_to_decimal(value)

convert something to a BigDecimal



166
167
168
169
170
171
172
173
174
175
176
177
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 166

def value_to_decimal(value)
  # Using .class is faster than .is_a? and
  # subclasses of BigDecimal will be handled
  # in the else clause
  if value.class == BigDecimal
    value
  elsif value.respond_to?(:to_d)
    value.to_d
  else
    value.to_s.to_d
  end
end

Instance Method Details

- (Object) extract_default(default) 



115
116
117
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 115

def extract_default(default)
  type_cast(default)
end

- (Boolean) has_default?

Returns:

  • (Boolean) 


52
53
54
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 52

def has_default?
  !default.nil?
end

- (Object) human_name

Returns the human name of the column name.

Examples
Column.new('sales_stage', ...).human_name # => 'Sales stage'


111
112
113
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 111

def human_name
  Base.human_attribute_name(@name)
end

- (Object) klass

Returns the Ruby class that corresponds to the abstract data type.



57
58
59
60
61
62
63
64
65
66
67
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 57

def klass
  case type
  when :integer                     then Fixnum
  when :float                       then Float
  when :decimal                     then BigDecimal
  when :datetime, :timestamp, :time then Time
  when :date                        then Date
  when :text, :string, :binary      then String
  when :boolean                     then Object
  end
end

- (Boolean) number?

Returns true if the column is either of type integer, float or decimal.

Returns:

  • (Boolean) 


48
49
50
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 48

def number?
  type == :integer || type == :float || type == :decimal
end

- (Object) string_to_binary(value)

Used to convert from Strings to BLOBs



120
121
122
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 120

def string_to_binary(value)
  self.class.string_to_binary(value)
end

- (Boolean) text?

Returns true if the column is either of type string or text.

Returns:

  • (Boolean) 


43
44
45
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 43

def text?
  type == :string || type == :text
end

- (Object) type_cast(value)

Casts value (which is a String) to an appropriate instance.



70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 70

def type_cast(value)
  return nil if value.nil?
  return coder.load(value) if encoded?

  klass = self.class

  case type
  when :string, :text        then value
  when :integer              then value.to_i rescue value ? 1 : 0
  when :float                then value.to_f
  when :decimal              then klass.value_to_decimal(value)
  when :datetime, :timestamp then klass.string_to_time(value)
  when :time                 then klass.string_to_dummy_time(value)
  when :date                 then klass.string_to_date(value)
  when :binary               then klass.binary_to_string(value)
  when :boolean              then klass.value_to_boolean(value)
  else value
  end
end

- (Object) type_cast_code(var_name) 



90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
 
# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 90

def type_cast_code(var_name)
  klass = self.class.name

  case type
  when :string, :text        then var_name
  when :integer              then "(#{var_name}.to_i rescue #{var_name} ? 1 : 0)"
  when :float                then "#{var_name}.to_f"
  when :decimal              then "#{klass}.value_to_decimal(#{var_name})"
  when :datetime, :timestamp then "#{klass}.string_to_time(#{var_name})"
  when :time                 then "#{klass}.string_to_dummy_time(#{var_name})"
  when :date                 then "#{klass}.string_to_date(#{var_name})"
  when :binary               then "#{klass}.binary_to_string(#{var_name})"
  when :boolean              then "#{klass}.value_to_boolean(#{var_name})"
  else var_name
  end
end