vendor/rails/activerecord/lib/active_record/schema_dumper.rb

   1 require 'stringio'
   2 require 'bigdecimal'
   3
   4 module ActiveRecord
   5   # This class is used to dump the database schema for some connection to some
   6   # output format (i.e., ActiveRecord::Schema).
   7   class SchemaDumper #:nodoc:
   8     private_class_method :new
   9
  10     # A list of tables which should not be dumped to the schema.
  11     # Acceptable values are strings as well as regexp.
  12     # This setting is only used if ActiveRecord::Base.schema_format == :ruby
  13     cattr_accessor :ignore_tables
  14     @@ignore_tables = []
  15
  16     def self.dump(connection=ActiveRecord::Base.connection, stream=STDOUT)
  17       new(connection).dump(stream)
  18       stream
  19     end
  20
  21     def dump(stream)
  22       header(stream)
  23       tables(stream)
  24       trailer(stream)
  25       stream
  26     end
  27
  28     private
  29
  30       def initialize(connection)
  31         @connection = connection
  32         @types = @connection.native_database_types
  33         @version = Migrator::current_version rescue nil
  34       end
  35
  36       def header(stream)
  37         define_params = @version ? ":version => #{@version}" : ""
  38
  39         stream.puts <<HEADER
  40 # This file is auto-generated from the current state of the database. Instead of editing this file,
  41 # please use the migrations feature of Active Record to incrementally modify your database, and
  42 # then regenerate this schema definition.
  43 #
  44 # Note that this schema.rb definition is the authoritative source for your database schema. If you need
  45 # to create the application database on another system, you should be using db:schema:load, not running
  46 # all the migrations from scratch. The latter is a flawed and unsustainable approach (the more migrations
  47 # you'll amass, the slower it'll run and the greater likelihood for issues).
  48 #
  49 # It's strongly recommended to check this file into your version control system.
  50
  51 ActiveRecord::Schema.define(#{define_params}) do
  52
  53 HEADER
  54       end
  55
  56       def trailer(stream)
  57         stream.puts "end"
  58       end
  59
  60       def tables(stream)
  61         @connection.tables.sort.each do |tbl|
  62           next if ['schema_migrations', ignore_tables].flatten.any? do |ignored|
  63             case ignored
  64             when String; tbl == ignored
  65             when Regexp; tbl =~ ignored
  66             else
  67               raise StandardError, 'ActiveRecord::SchemaDumper.ignore_tables accepts an array of String and / or Regexp values.'
  68             end
  69           end
  70           table(tbl, stream)
  71         end
  72       end
  73
  74       def table(table, stream)
  75         columns = @connection.columns(table)
  76         begin
  77           tbl = StringIO.new
  78
  79           if @connection.respond_to?(:pk_and_sequence_for)
  80             pk, pk_seq = @connection.pk_and_sequence_for(table)
  81           end
  82           pk ||= 'id'
  83
  84           tbl.print "  create_table #{table.inspect}"
  85           if columns.detect { |c| c.name == pk }
  86             if pk != 'id'
  87               tbl.print %Q(, :primary_key => "#{pk}")
  88             end
  89           else
  90             tbl.print ", :id => false"
  91           end
  92           tbl.print ", :force => true"
  93           tbl.puts " do |t|"
  94
  95           column_specs = columns.map do |column|
  96             raise StandardError, "Unknown type '#{column.sql_type}' for column '#{column.name}'" if @types[column.type].nil?
  97             next if column.name == pk
  98             spec = {}
  99             spec[:name]      = column.name.inspect
 100             spec[:type]      = column.type.to_s
 101             spec[:limit]     = column.limit.inspect if column.limit != @types[column.type][:limit] && column.type != :decimal
 102             spec[:precision] = column.precision.inspect if !column.precision.nil?
 103             spec[:scale]     = column.scale.inspect if !column.scale.nil?
 104             spec[:null]      = 'false' if !column.null
 105             spec[:default]   = default_string(column.default) if column.has_default?
 106             (spec.keys - [:name, :type]).each{ |k| spec[k].insert(0, "#{k.inspect} => ")}
 107             spec
 108           end.compact
 109
 110           # find all migration keys used in this table
 111           keys = [:name, :limit, :precision, :scale, :default, :null] & column_specs.map(&:keys).flatten
 112
 113           # figure out the lengths for each column based on above keys
 114           lengths = keys.map{ |key| column_specs.map{ |spec| spec[key] ? spec[key].length + 2 : 0 }.max }
 115
 116           # the string we're going to sprintf our values against, with standardized column widths
 117           format_string = lengths.map{ |len| "%-#{len}s" }
 118
 119           # find the max length for the 'type' column, which is special
 120           type_length = column_specs.map{ |column| column[:type].length }.max
 121
 122           # add column type definition to our format string
 123           format_string.unshift "    t.%-#{type_length}s "
 124
 125           format_string *= ''
 126
 127           column_specs.each do |colspec|
 128             values = keys.zip(lengths).map{ |key, len| colspec.key?(key) ? colspec[key] + ", " : " " * len }
 129             values.unshift colspec[:type]
 130             tbl.print((format_string % values).gsub(/,\s*$/, ''))
 131             tbl.puts
 132           end
 133
 134           tbl.puts "  end"
 135           tbl.puts
 136
 137           indexes(table, tbl)
 138
 139           tbl.rewind
 140           stream.print tbl.read
 141         rescue => e
 142           stream.puts "# Could not dump table #{table.inspect} because of following #{e.class}"
 143           stream.puts "#   #{e.message}"
 144           stream.puts
 145         end
 146
 147         stream
 148       end
 149
 150       def default_string(value)
 151         case value
 152         when BigDecimal
 153           value.to_s
 154         when Date, DateTime, Time
 155           "'" + value.to_s(:db) + "'"
 156         else
 157           value.inspect
 158         end
 159       end
 160
 161       def indexes(table, stream)
 162         if (indexes = @connection.indexes(table)).any?
 163           add_index_statements = indexes.map do |index|
 164             statment_parts = [ ('add_index ' + index.table.inspect) ]
 165             statment_parts << index.columns.inspect
 166             statment_parts << (':name => ' + index.name.inspect)
 167             statment_parts << ':unique => true' if index.unique
 168
 169             '  ' + statment_parts.join(', ')
 170           end
 171
 172           stream.puts add_index_statements.sort.join("\n")
 173           stream.puts
 174         end
 175       end
 176   end
 177 end