require 'date'
require 'bigdecimal'
require 'bigdecimal/util'
module ActiveRecord
module ConnectionAdapters #:nodoc:
# An abstract definition of a column in a table.
class Column
attr_reader :name, :default, :type, :limit, :null, :sql_type, :precision, :scale
attr_accessor :primary
# Instantiates a new column in the table.
#
# +name+ is the column's name, as in supplier_id int(11).
# +default+ is the type-casted default value, such as sales_stage varchar(20) default 'new'.
# +sql_type+ is only used to extract the column's length, if necessary. For example, company_name varchar(60).
# +null+ determines if this column allows +NULL+ values.
def initialize(name, default, sql_type = nil, null = true)
@name, @sql_type, @null = name, sql_type, null
@limit, @precision, @scale = extract_limit(sql_type), extract_precision(sql_type), extract_scale(sql_type)
@type = simplified_type(sql_type)
@default = type_cast(default)
@primary = nil
end
def text?
[:string, :text].include? type
end
def number?
[:float, :integer, :decimal].include? type
end
# Returns the Ruby class that corresponds to the abstract data type.
def klass
case type
when :integer then Fixnum
when :float then Float
when :decimal then BigDecimal
when :datetime then Time
when :date then Date
when :timestamp then Time
when :time then Time
when :text, :string then String
when :binary then String
when :boolean then Object
end
end
# Casts value (which is a String) to an appropriate instance.
def type_cast(value)
return nil if value.nil?
case type
when :string then value
when :text then value
when :integer then value.to_i rescue value ? 1 : 0
when :float then value.to_f
when :decimal then self.class.value_to_decimal(value)
when :datetime then self.class.string_to_time(value)
when :timestamp then self.class.string_to_time(value)
when :time then self.class.string_to_dummy_time(value)
when :date then self.class.string_to_date(value)
when :binary then self.class.binary_to_string(value)
when :boolean then self.class.value_to_boolean(value)
else value
end
end
def type_cast_code(var_name)
case type
when :string then nil
when :text then nil
when :integer then "(#{var_name}.to_i rescue #{var_name} ? 1 : 0)"
when :float then "#{var_name}.to_f"
when :decimal then "#{self.class.name}.value_to_decimal(#{var_name})"
when :datetime then "#{self.class.name}.string_to_time(#{var_name})"
when :timestamp then "#{self.class.name}.string_to_time(#{var_name})"
when :time then "#{self.class.name}.string_to_dummy_time(#{var_name})"
when :date then "#{self.class.name}.string_to_date(#{var_name})"
when :binary then "#{self.class.name}.binary_to_string(#{var_name})"
when :boolean then "#{self.class.name}.value_to_boolean(#{var_name})"
else nil
end
end
# Returns the human name of the column name.
#
# ===== Examples
# Column.new('sales_stage', ...).human_name #=> 'Sales stage'
def human_name
Base.human_attribute_name(@name)
end
# Used to convert from Strings to BLOBs
def self.string_to_binary(value)
value
end
# Used to convert from BLOBs to Strings
def self.binary_to_string(value)
value
end
def self.string_to_date(string)
return string unless string.is_a?(String)
date_array = ParseDate.parsedate(string)
# treat 0000-00-00 as nil
Date.new(date_array[0], date_array[1], date_array[2]) rescue nil
end
def self.string_to_time(string)
return string unless string.is_a?(String)
time_hash = Date._parse(string)
time_hash[:sec_fraction] = microseconds(time_hash)
time_array = time_hash.values_at(:year, :mon, :mday, :hour, :min, :sec, :sec_fraction)
# treat 0000-00-00 00:00:00 as nil
Time.send(Base.default_timezone, *time_array) rescue DateTime.new(*time_array[0..5]) rescue nil
end
def self.string_to_dummy_time(string)
return string unless string.is_a?(String)
return nil if string.empty?
time_hash = Date._parse(string)
time_hash[:sec_fraction] = microseconds(time_hash)
# pad the resulting array with dummy date information
time_array = [2000, 1, 1]
time_array += time_hash.values_at(:hour, :min, :sec, :sec_fraction)
Time.send(Base.default_timezone, *time_array) rescue nil
end
# convert something to a boolean
def self.value_to_boolean(value)
if value == true || value == false
value
else
%w(true t 1).include?(value.to_s.downcase)
end
end
# convert something to a BigDecimal
def self.value_to_decimal(value)
if value.is_a?(BigDecimal)
value
elsif value.respond_to?(:to_d)
value.to_d
else
value.to_s.to_d
end
end
private
# '0.123456' -> 123456
# '1.123456' -> 123456
def self.microseconds(time)
((time[:sec_fraction].to_f % 1) * 1_000_000).to_i
end
def extract_limit(sql_type)
$1.to_i if sql_type =~ /\((.*)\)/
end
def extract_precision(sql_type)
$2.to_i if sql_type =~ /^(numeric|decimal|number)\((\d+)(,\d+)?\)/i
end
def extract_scale(sql_type)
case sql_type
when /^(numeric|decimal|number)\((\d+)\)/i then 0
when /^(numeric|decimal|number)\((\d+)(,(\d+))\)/i then $4.to_i
end
end
def simplified_type(field_type)
case field_type
when /int/i
:integer
when /float|double/i
:float
when /decimal|numeric|number/i
extract_scale(field_type) == 0 ? :integer : :decimal
when /datetime/i
:datetime
when /timestamp/i
:timestamp
when /time/i
:time
when /date/i
:date
when /clob/i, /text/i
:text
when /blob/i, /binary/i
:binary
when /char/i, /string/i
:string
when /boolean/i
:boolean
end
end
end
class IndexDefinition < Struct.new(:table, :name, :unique, :columns) #:nodoc:
end
class ColumnDefinition < Struct.new(:base, :name, :type, :limit, :precision, :scale, :default, :null) #:nodoc:
def to_sql
column_sql = "#{base.quote_column_name(name)} #{type_to_sql(type.to_sym, limit, precision, scale)}"
add_column_options!(column_sql, :null => null, :default => default)
column_sql
end
alias to_s :to_sql
private
def type_to_sql(name, limit, precision, scale)
base.type_to_sql(name, limit, precision, scale) rescue name
end
def add_column_options!(sql, options)
base.add_column_options!(sql, options.merge(:column => self))
end
end
# Represents a SQL table in an abstract way.
# Columns are stored as ColumnDefinition in the #columns attribute.
class TableDefinition
attr_accessor :columns
def initialize(base)
@columns = []
@base = base
end
# Appends a primary key definition to the table definition.
# Can be called multiple times, but this is probably not a good idea.
def primary_key(name)
column(name, native[:primary_key])
end
# Returns a ColumnDefinition for the column with name +name+.
def [](name)
@columns.find {|column| column.name.to_s == name.to_s}
end
# Instantiates a new column for the table.
# The +type+ parameter must be one of the following values:
# :primary_key, :string, :text,
# :integer, :float, :decimal,
# :datetime, :timestamp, :time,
# :date, :binary, :boolean.
#
# Available options are (none of these exists by default):
# * :limit:
# Requests a maximum column length (:string, :text,
# :binary or :integer columns only)
# * :default:
# The column's default value. You cannot explicitely set the default
# value to +NULL+. Simply leave off this option if you want a +NULL+
# default value.
# * :null:
# Allows or disallows +NULL+ values in the column. This option could
# have been named :null_allowed.
# * :precision:
# Specifies the precision for a :decimal column.
# * :scale:
# Specifies the scale for a :decimal column.
#
# Please be aware of different RDBMS implementations behavior with
# :decimal columns:
# * The SQL standard says the default scale should be 0, :scale <=
# :precision, and makes no comments about the requirements of
# :precision.
# * MySQL: :precision [1..63], :scale [0..30].
# Default is (10,0).
# * PostGres?: :precision [1..infinity],
# :scale [0..infinity]. No default.
# * Sqlite2: Any :precision and :scale may be used.
# Internal storage as strings. No default.
# * Sqlite3: No restrictions on :precision and :scale,
# but the maximum supported :precision is 16. No default.
# * Oracle: :precision [1..38], :scale [-84..127].
# Default is (38,0).
# * DB2: :precision [1..63], :scale [0..62].
# Default unknown.
# * Firebird: :precision [1..18], :scale [0..18].
# Default (9,0). Internal types NUMERIC and DECIMAL have different
# storage rules, decimal being better.
# * FrontBase?: :precision [1..38], :scale [0..38].
# Default (38,0). WARNING Max :precision/:scale for
# NUMERIC is 19, and DECIMAL is 38.
# * SqlServer?: :precision [1..38], :scale [0..38].
# Default (38,0).
# * Sybase: :precision [1..38], :scale [0..38].
# Default (38,0).
# * OpenBase?: Documentation unclear. Claims storage in double.
#
# This method returns self.
#
# ===== Examples
# # Assuming td is an instance of TableDefinition
# td.column(:granted, :boolean)
# #=> granted BOOLEAN
#
# td.column(:picture, :binary, :limit => 2.megabytes)
# #=> picture BLOB(2097152)
#
# td.column(:sales_stage, :string, :limit => 20, :default => 'new', :null => false)
# #=> sales_stage VARCHAR(20) DEFAULT 'new' NOT NULL
#
# def.column(:bill_gates_money, :decimal, :precision => 15, :scale => 2)
# #=> bill_gates_money DECIMAL(15,2)
#
# def.column(:sensor_reading, :decimal, :precision => 30, :scale => 20)
# #=> sensor_reading DECIMAL(30,20)
#
# # While :scale defaults to zero on most databases, it
# # probably wouldn't hurt to include it.
# def.column(:huge_integer, :decimal, :precision => 30)
# #=> huge_integer DECIMAL(30)
def column(name, type, options = {})
column = self[name] || ColumnDefinition.new(@base, name, type)
column.limit = options[:limit] || native[type.to_sym][:limit] if options[:limit] or native[type.to_sym]
column.precision = options[:precision]
column.scale = options[:scale]
column.default = options[:default]
column.null = options[:null]
@columns << column unless @columns.include? column
self
end
# Returns a String whose contents are the column definitions
# concatenated together. This string can then be pre and appended to
# to generate the final SQL to create the table.
def to_sql
@columns * ', '
end
private
def native
@base.native_database_types
end
end
end
end