aboutsummaryrefslogtreecommitdiffstats
path: root/activerecord/lib/active_record/schema_dumper.rb
blob: 557a55496676404bb03fb89b12a63855eda43366 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
require 'stringio'
require 'bigdecimal'

module ActiveRecord
  # This class is used to dump the database schema for some connection to some
  # output format (i.e., ActiveRecord::Schema).
  class SchemaDumper #:nodoc:
    private_class_method :new
    
    ##
    # :singleton-method:
    # A list of tables which should not be dumped to the schema. 
    # Acceptable values are strings as well as regexp.
    # This setting is only used if ActiveRecord::Base.schema_format == :ruby
    cattr_accessor :ignore_tables 
    @@ignore_tables = []

    def self.dump(connection=ActiveRecord::Base.connection, stream=STDOUT)
      new(connection).dump(stream)
      stream
    end

    def dump(stream)
      header(stream)
      tables(stream)
      trailer(stream)
      stream
    end

    private

      def initialize(connection)
        @connection = connection
        @types = @connection.native_database_types
        @version = Migrator::current_version rescue nil
      end

      def header(stream)
        define_params = @version ? ":version => #{@version}" : ""

        stream.puts <<HEADER
# This file is auto-generated from the current state of the database. Instead of editing this file, 
# please use the migrations feature of Active Record to incrementally modify your database, and
# then regenerate this schema definition.
#
# Note that this schema.rb definition is the authoritative source for your database schema. If you need
# to create the application database on another system, you should be using db:schema:load, not running
# all the migrations from scratch. The latter is a flawed and unsustainable approach (the more migrations
# you'll amass, the slower it'll run and the greater likelihood for issues).
#
# It's strongly recommended to check this file into your version control system.

ActiveRecord::Schema.define(#{define_params}) do

HEADER
      end

      def trailer(stream)
        stream.puts "end"
      end

      def tables(stream)
        @connection.tables.sort.each do |tbl|
          next if ['schema_migrations', ignore_tables].flatten.any? do |ignored|
            case ignored
            when String; tbl == ignored
            when Regexp; tbl =~ ignored
            else
              raise StandardError, 'ActiveRecord::SchemaDumper.ignore_tables accepts an array of String and / or Regexp values.'
            end
          end 
          table(tbl, stream)
        end
      end

      def table(table, stream)
        columns = @connection.columns(table)
        begin
          tbl = StringIO.new

          if @connection.respond_to?(:pk_and_sequence_for)
            pk, pk_seq = @connection.pk_and_sequence_for(table)
          end
          pk ||= 'id'

          tbl.print "  create_table #{table.inspect}"
          if columns.detect { |c| c.name == pk }
            if pk != 'id'
              tbl.print %Q(, :primary_key => "#{pk}")
            end
          else
            tbl.print ", :id => false"
          end
          tbl.print ", :force => true"
          tbl.puts " do |t|"

          column_specs = columns.map do |column|
            raise StandardError, "Unknown type '#{column.sql_type}' for column '#{column.name}'" if @types[column.type].nil?
            next if column.name == pk
            spec = {}
            spec[:name]      = column.name.inspect
            spec[:type]      = column.type.to_s
            spec[:limit]     = column.limit.inspect if column.limit != @types[column.type][:limit] && column.type != :decimal
            spec[:precision] = column.precision.inspect if !column.precision.nil?
            spec[:scale]     = column.scale.inspect if !column.scale.nil?
            spec[:null]      = 'false' if !column.null
            spec[:default]   = default_string(column.default) if column.has_default?
            (spec.keys - [:name, :type]).each{ |k| spec[k].insert(0, "#{k.inspect} => ")}
            spec
          end.compact

          # find all migration keys used in this table
          keys = [:name, :limit, :precision, :scale, :default, :null] & column_specs.map(&:keys).flatten

          # figure out the lengths for each column based on above keys
          lengths = keys.map{ |key| column_specs.map{ |spec| spec[key] ? spec[key].length + 2 : 0 }.max }

          # the string we're going to sprintf our values against, with standardized column widths
          format_string = lengths.map{ |len| "%-#{len}s" }

          # find the max length for the 'type' column, which is special
          type_length = column_specs.map{ |column| column[:type].length }.max

          # add column type definition to our format string
          format_string.unshift "    t.%-#{type_length}s "

          format_string *= ''

          column_specs.each do |colspec|
            values = keys.zip(lengths).map{ |key, len| colspec.key?(key) ? colspec[key] + ", " : " " * len }
            values.unshift colspec[:type]
            tbl.print((format_string % values).gsub(/,\s*$/, ''))
            tbl.puts
          end

          tbl.puts "  end"
          tbl.puts
          
          indexes(table, tbl)

          tbl.rewind
          stream.print tbl.read
        rescue => e
          stream.puts "# Could not dump table #{table.inspect} because of following #{e.class}"
          stream.puts "#   #{e.message}"
          stream.puts
        end
        
        stream
      end

      def default_string(value)
        case value
        when BigDecimal
          value.to_s
        when Date, DateTime, Time
          "'" + value.to_s(:db) + "'"
        else
          value.inspect
        end
      end
      
      def indexes(table, stream)
        if (indexes = @connection.indexes(table)).any?
          add_index_statements = indexes.map do |index|
            statment_parts = [ ('add_index ' + index.table.inspect) ]
            statment_parts << index.columns.inspect
            statment_parts << (':name => ' + index.name.inspect)
            statment_parts << ':unique => true' if index.unique

            '  ' + statment_parts.join(', ')
          end

          stream.puts add_index_statements.sort.join("\n")
          stream.puts
        end
      end
  end
end