344 lines
12 KiB
Ruby
344 lines
12 KiB
Ruby
require 'date'
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require 'bigdecimal'
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require 'bigdecimal/util'
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module ActiveRecord
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module ConnectionAdapters #:nodoc:
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# An abstract definition of a column in a table.
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class Column
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attr_reader :name, :default, :type, :limit, :null, :sql_type, :precision, :scale
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attr_accessor :primary
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# Instantiates a new column in the table.
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#
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# +name+ is the column's name, as in <tt><b>supplier_id</b> int(11)</tt>.
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# +default+ is the type-casted default value, such as <tt>sales_stage varchar(20) default <b>'new'</b></tt>.
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# +sql_type+ is only used to extract the column's length, if necessary. For example, <tt>company_name varchar(<b>60</b>)</tt>.
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# +null+ determines if this column allows +NULL+ values.
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def initialize(name, default, sql_type = nil, null = true)
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@name, @sql_type, @null = name, sql_type, null
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@limit, @precision, @scale = extract_limit(sql_type), extract_precision(sql_type), extract_scale(sql_type)
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@type = simplified_type(sql_type)
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@default = type_cast(default)
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@primary = nil
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end
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def text?
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[:string, :text].include? type
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end
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def number?
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[:float, :integer, :decimal].include? type
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end
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# Returns the Ruby class that corresponds to the abstract data type.
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def klass
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case type
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when :integer then Fixnum
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when :float then Float
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when :decimal then BigDecimal
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when :datetime then Time
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when :date then Date
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when :timestamp then Time
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when :time then Time
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when :text, :string then String
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when :binary then String
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when :boolean then Object
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end
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end
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# Casts value (which is a String) to an appropriate instance.
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def type_cast(value)
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return nil if value.nil?
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case type
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when :string then value
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when :text then value
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when :integer then value.to_i rescue value ? 1 : 0
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when :float then value.to_f
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when :decimal then self.class.value_to_decimal(value)
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when :datetime then self.class.string_to_time(value)
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when :timestamp then self.class.string_to_time(value)
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when :time then self.class.string_to_dummy_time(value)
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when :date then self.class.string_to_date(value)
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when :binary then self.class.binary_to_string(value)
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when :boolean then self.class.value_to_boolean(value)
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else value
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end
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end
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def type_cast_code(var_name)
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case type
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when :string then nil
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when :text then nil
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when :integer then "(#{var_name}.to_i rescue #{var_name} ? 1 : 0)"
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when :float then "#{var_name}.to_f"
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when :decimal then "#{self.class.name}.value_to_decimal(#{var_name})"
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when :datetime then "#{self.class.name}.string_to_time(#{var_name})"
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when :timestamp then "#{self.class.name}.string_to_time(#{var_name})"
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when :time then "#{self.class.name}.string_to_dummy_time(#{var_name})"
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when :date then "#{self.class.name}.string_to_date(#{var_name})"
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when :binary then "#{self.class.name}.binary_to_string(#{var_name})"
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when :boolean then "#{self.class.name}.value_to_boolean(#{var_name})"
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else nil
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end
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end
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# Returns the human name of the column name.
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#
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# ===== Examples
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# Column.new('sales_stage', ...).human_name #=> 'Sales stage'
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def human_name
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Base.human_attribute_name(@name)
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end
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# Used to convert from Strings to BLOBs
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def self.string_to_binary(value)
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value
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end
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# Used to convert from BLOBs to Strings
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def self.binary_to_string(value)
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value
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end
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def self.string_to_date(string)
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return string unless string.is_a?(String)
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date_array = ParseDate.parsedate(string)
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# treat 0000-00-00 as nil
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Date.new(date_array[0], date_array[1], date_array[2]) rescue nil
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end
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def self.string_to_time(string)
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return string unless string.is_a?(String)
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time_hash = Date._parse(string)
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time_hash[:sec_fraction] = microseconds(time_hash)
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time_array = time_hash.values_at(:year, :mon, :mday, :hour, :min, :sec, :sec_fraction)
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# treat 0000-00-00 00:00:00 as nil
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Time.send(Base.default_timezone, *time_array) rescue DateTime.new(*time_array[0..5]) rescue nil
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end
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def self.string_to_dummy_time(string)
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return string unless string.is_a?(String)
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return nil if string.empty?
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time_hash = Date._parse(string)
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time_hash[:sec_fraction] = microseconds(time_hash)
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# pad the resulting array with dummy date information
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time_array = [2000, 1, 1]
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time_array += time_hash.values_at(:hour, :min, :sec, :sec_fraction)
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Time.send(Base.default_timezone, *time_array) rescue nil
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end
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# convert something to a boolean
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def self.value_to_boolean(value)
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if value == true || value == false
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value
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else
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%w(true t 1).include?(value.to_s.downcase)
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end
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end
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# convert something to a BigDecimal
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def self.value_to_decimal(value)
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if value.is_a?(BigDecimal)
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value
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elsif value.respond_to?(:to_d)
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value.to_d
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else
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value.to_s.to_d
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end
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end
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private
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# '0.123456' -> 123456
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# '1.123456' -> 123456
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def self.microseconds(time)
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((time[:sec_fraction].to_f % 1) * 1_000_000).to_i
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end
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def extract_limit(sql_type)
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$1.to_i if sql_type =~ /\((.*)\)/
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end
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def extract_precision(sql_type)
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$2.to_i if sql_type =~ /^(numeric|decimal|number)\((\d+)(,\d+)?\)/i
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end
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def extract_scale(sql_type)
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case sql_type
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when /^(numeric|decimal|number)\((\d+)\)/i then 0
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when /^(numeric|decimal|number)\((\d+)(,(\d+))\)/i then $4.to_i
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end
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end
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def simplified_type(field_type)
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case field_type
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when /int/i
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:integer
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when /float|double/i
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:float
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when /decimal|numeric|number/i
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extract_scale(field_type) == 0 ? :integer : :decimal
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when /datetime/i
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:datetime
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when /timestamp/i
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:timestamp
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when /time/i
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:time
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when /date/i
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:date
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when /clob/i, /text/i
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:text
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when /blob/i, /binary/i
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:binary
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when /char/i, /string/i
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:string
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when /boolean/i
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:boolean
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end
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end
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end
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class IndexDefinition < Struct.new(:table, :name, :unique, :columns) #:nodoc:
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end
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class ColumnDefinition < Struct.new(:base, :name, :type, :limit, :precision, :scale, :default, :null) #:nodoc:
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def sql_type
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base.type_to_sql(type.to_sym, limit, precision, scale) rescue type
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end
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def to_sql
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column_sql = "#{base.quote_column_name(name)} #{sql_type}"
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add_column_options!(column_sql, :null => null, :default => default) unless type.to_sym == :primary_key
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column_sql
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end
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alias to_s :to_sql
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private
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def add_column_options!(sql, options)
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base.add_column_options!(sql, options.merge(:column => self))
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end
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end
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# Represents a SQL table in an abstract way.
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# Columns are stored as ColumnDefinition in the #columns attribute.
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class TableDefinition
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attr_accessor :columns
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def initialize(base)
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@columns = []
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@base = base
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end
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# Appends a primary key definition to the table definition.
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# Can be called multiple times, but this is probably not a good idea.
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def primary_key(name)
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column(name, :primary_key)
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end
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# Returns a ColumnDefinition for the column with name +name+.
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def [](name)
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@columns.find {|column| column.name.to_s == name.to_s}
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end
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# Instantiates a new column for the table.
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# The +type+ parameter must be one of the following values:
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# <tt>:primary_key</tt>, <tt>:string</tt>, <tt>:text</tt>,
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# <tt>:integer</tt>, <tt>:float</tt>, <tt>:decimal</tt>,
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# <tt>:datetime</tt>, <tt>:timestamp</tt>, <tt>:time</tt>,
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# <tt>:date</tt>, <tt>:binary</tt>, <tt>:boolean</tt>.
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#
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# Available options are (none of these exists by default):
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# * <tt>:limit</tt>:
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# Requests a maximum column length (<tt>:string</tt>, <tt>:text</tt>,
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# <tt>:binary</tt> or <tt>:integer</tt> columns only)
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# * <tt>:default</tt>:
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# The column's default value. Use nil for NULL.
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# * <tt>:null</tt>:
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# Allows or disallows +NULL+ values in the column. This option could
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# have been named <tt>:null_allowed</tt>.
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# * <tt>:precision</tt>:
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# Specifies the precision for a <tt>:decimal</tt> column.
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# * <tt>:scale</tt>:
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# Specifies the scale for a <tt>:decimal</tt> column.
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#
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# Please be aware of different RDBMS implementations behavior with
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# <tt>:decimal</tt> columns:
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# * The SQL standard says the default scale should be 0, <tt>:scale</tt> <=
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# <tt>:precision</tt>, and makes no comments about the requirements of
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# <tt>:precision</tt>.
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# * MySQL: <tt>:precision</tt> [1..63], <tt>:scale</tt> [0..30].
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# Default is (10,0).
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# * PostgreSQL: <tt>:precision</tt> [1..infinity],
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# <tt>:scale</tt> [0..infinity]. No default.
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# * SQLite2: Any <tt>:precision</tt> and <tt>:scale</tt> may be used.
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# Internal storage as strings. No default.
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# * SQLite3: No restrictions on <tt>:precision</tt> and <tt>:scale</tt>,
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# but the maximum supported <tt>:precision</tt> is 16. No default.
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# * Oracle: <tt>:precision</tt> [1..38], <tt>:scale</tt> [-84..127].
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# Default is (38,0).
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# * DB2: <tt>:precision</tt> [1..63], <tt>:scale</tt> [0..62].
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# Default unknown.
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# * Firebird: <tt>:precision</tt> [1..18], <tt>:scale</tt> [0..18].
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# Default (9,0). Internal types NUMERIC and DECIMAL have different
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# storage rules, decimal being better.
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# * FrontBase?: <tt>:precision</tt> [1..38], <tt>:scale</tt> [0..38].
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# Default (38,0). WARNING Max <tt>:precision</tt>/<tt>:scale</tt> for
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# NUMERIC is 19, and DECIMAL is 38.
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# * SqlServer?: <tt>:precision</tt> [1..38], <tt>:scale</tt> [0..38].
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# Default (38,0).
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# * Sybase: <tt>:precision</tt> [1..38], <tt>:scale</tt> [0..38].
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# Default (38,0).
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# * OpenBase?: Documentation unclear. Claims storage in <tt>double</tt>.
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#
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# This method returns <tt>self</tt>.
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#
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# ===== Examples
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# # Assuming td is an instance of TableDefinition
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# td.column(:granted, :boolean)
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# #=> granted BOOLEAN
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#
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# td.column(:picture, :binary, :limit => 2.megabytes)
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# #=> picture BLOB(2097152)
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#
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# td.column(:sales_stage, :string, :limit => 20, :default => 'new', :null => false)
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# #=> sales_stage VARCHAR(20) DEFAULT 'new' NOT NULL
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#
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# def.column(:bill_gates_money, :decimal, :precision => 15, :scale => 2)
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# #=> bill_gates_money DECIMAL(15,2)
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#
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# def.column(:sensor_reading, :decimal, :precision => 30, :scale => 20)
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# #=> sensor_reading DECIMAL(30,20)
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#
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# # While <tt>:scale</tt> defaults to zero on most databases, it
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# # probably wouldn't hurt to include it.
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# def.column(:huge_integer, :decimal, :precision => 30)
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# #=> huge_integer DECIMAL(30)
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def column(name, type, options = {})
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column = self[name] || ColumnDefinition.new(@base, name, type)
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column.limit = options[:limit] || native[type.to_sym][:limit] if options[:limit] or native[type.to_sym]
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column.precision = options[:precision]
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column.scale = options[:scale]
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column.default = options[:default]
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column.null = options[:null]
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@columns << column unless @columns.include? column
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self
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end
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# Returns a String whose contents are the column definitions
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# concatenated together. This string can then be pre and appended to
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# to generate the final SQL to create the table.
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def to_sql
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@columns * ', '
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end
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private
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def native
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@base.native_database_types
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end
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end
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end
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end
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