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