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.

Direct Known Subclasses

AbstractMysqlAdapter::Column, PostgreSQLColumn, SQLite3Column

Defined Under Namespace

Modules: Format

Constant Summary

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

- (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.



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# 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)
  @default_function = nil
  @primary          = nil
  @coder            = nil
end

Instance Attribute Details

- (Object) coder Also known as: encoded?

Returns the value of attribute coder



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

def coder
  @coder
end

- (Object) default (readonly)

Returns the value of attribute default



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

def default
  @default
end

- (Object) default_function (readonly)

Returns the value of attribute default_function



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

def default_function
  @default_function
end

- (Object) limit (readonly)

Returns the value of attribute limit



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

def limit
  @limit
end

- (Object) name (readonly)

Returns the value of attribute name



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

def name
  @name
end

- (Object) null (readonly)

Returns the value of attribute null



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

def null
  @null
end

- (Object) precision (readonly)

Returns the value of attribute precision



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

def precision
  @precision
end

- (Object) primary

Returns the value of attribute primary



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

def primary
  @primary
end

- (Object) scale (readonly)

Returns the value of attribute scale



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# 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



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# 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



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# 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



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

def binary_to_string(value)
  value
end

+ (Object) string_to_dummy_time(string)



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# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 153

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

+ (Object) string_to_time(string)



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# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 146

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



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# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 167

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

+ (Object) value_to_date(value)



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# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 135

def value_to_date(value)
  if value.is_a?(String)
    return nil if value.empty?
    fast_string_to_date(value) || fallback_string_to_date(value)
  elsif value.respond_to?(:to_date)
    value.to_date
  else
    value
  end
end

+ (Object) value_to_decimal(value)

convert something to a BigDecimal



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# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 187

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

+ (Object) value_to_integer(value)

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



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# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 177

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

Instance Method Details

- (Boolean) binary?

Returns:

  • (Boolean)


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# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 70

def binary?
  type == :binary
end

- (Object) extract_default(default)



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# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 125

def extract_default(default)
  type_cast(default)
end

- (Boolean) has_default?

Returns:

  • (Boolean)


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

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'


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

def human_name
  Base.human_attribute_name(@name)
end

- (Object) klass

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



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# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 58

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)


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

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

- (Boolean) text?

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

Returns:

  • (Boolean)


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

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

- (Object) type_cast(value)

Casts value to an appropriate instance.



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# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 91

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

  klass = self.class

  case type
  when :string, :text
    case value
    when TrueClass; "1"
    when FalseClass; "0"
    else
      value.to_s
    end
  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.value_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_for_write(value)

Casts a Ruby value to something appropriate for writing to the database.



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# File 'activerecord/lib/active_record/connection_adapters/column.rb', line 75

def type_cast_for_write(value)
  return value unless number?

  case value
  when FalseClass
    0
  when TrueClass
    1
  when String
    value.presence
  else
    value
  end
end