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 sql_type base.type_to_sql(type.to_sym, limit, precision, scale) rescue type end def to_sql column_sql = "#{base.quote_column_name(name)} #{sql_type}" add_column_options!(column_sql, :null => null, :default => default) unless type.to_sym == :primary_key column_sql end alias to_s :to_sql private 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, :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. Use nil for NULL. # * :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). # * PostgreSQL: :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