Class: ActiveRecord::ConnectionAdapters::Column

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

Overview

An abstract definition of a column in a table.

Defined Under Namespace

Modules: Format

Constant Summary collapse

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

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

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

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.


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# File '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

#coderObject Also known as: encoded?

Returns the value of attribute coder


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

def coder
  @coder
end

#defaultObject (readonly)

Returns the value of attribute default


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

def default
  @default
end

#limitObject (readonly)

Returns the value of attribute limit


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

def limit
  @limit
end

#nameObject (readonly)

Returns the value of attribute name


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

def name
  @name
end

#nullObject (readonly)

Returns the value of attribute null


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

def null
  @null
end

#precisionObject (readonly)

Returns the value of attribute precision


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

def precision
  @precision
end

#primaryObject

Returns the value of attribute primary


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

def primary
  @primary
end

#scaleObject (readonly)

Returns the value of attribute scale


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

def scale
  @scale
end

#sql_typeObject (readonly)

Returns the value of attribute sql_type


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

def sql_type
  @sql_type
end

#typeObject (readonly)

Returns the value of attribute type


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

def type
  @type
end

Class Method Details

.binary_to_string(value) ⇒ Object

Used to convert from BLOBs to Strings


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

def binary_to_string(value)
  value
end

.string_to_binary(value) ⇒ Object

Used to convert from Strings to BLOBs


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

def string_to_binary(value)
  value
end

.string_to_date(string) ⇒ Object


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# File '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

.string_to_dummy_time(string) ⇒ Object


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# File '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?

  dummy_time_string = "2000-01-01 #{string}"

  fast_string_to_time(dummy_time_string) || begin
    time_hash = Date._parse(dummy_time_string)
    return nil if time_hash[:hour].nil?
    new_time(*time_hash.values_at(:year, :mon, :mday, :hour, :min, :sec, :sec_fraction))
  end
end

.string_to_time(string) ⇒ Object


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# File '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

.value_to_boolean(value) ⇒ Object

convert something to a boolean


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# File 'lib/active_record/connection_adapters/column.rb', line 163

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

.value_to_decimal(value) ⇒ Object

convert something to a BigDecimal


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# File 'lib/active_record/connection_adapters/column.rb', line 183

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

.value_to_integer(value) ⇒ Object

Used to convert values to integer. handle the case when an integer column is used to store boolean values


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# File 'lib/active_record/connection_adapters/column.rb', line 173

def value_to_integer(value)
  case value
  when TrueClass, FalseClass
    value ? 1 : 0
  else
    value.to_i rescue nil
  end
end

Instance Method Details

#extract_default(default) ⇒ Object


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

def extract_default(default)
  type_cast(default)
end

#has_default?Boolean

Returns:

  • (Boolean)

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

def has_default?
  !default.nil?
end

#human_nameObject

Returns the human name of the column name.

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

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

def human_name
  Base.human_attribute_name(@name)
end

#klassObject

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


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# File '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

#number?Boolean

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

Returns:

  • (Boolean)

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

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

#string_to_binary(value) ⇒ Object

Used to convert from Strings to BLOBs


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

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

#text?Boolean

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

Returns:

  • (Boolean)

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

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

#type_cast(value) ⇒ Object

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


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# File '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 klass.value_to_integer(value)
  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

#type_cast_code(var_name) ⇒ Object


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# File '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 "#{klass}.value_to_integer(#{var_name})"
  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