Source

RubyLearning / ProjectTrak / vendor / rails / activerecord / lib / active_record / connection_adapters / abstract / schema_statements.rb

Full commit
  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
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
module ActiveRecord
  module ConnectionAdapters # :nodoc:
    module SchemaStatements
      # Returns a Hash of mappings from the abstract data types to the native
      # database types.  See TableDefinition#column for details on the recognized
      # abstract data types.
      def native_database_types
        {}
      end

      # This is the maximum length a table alias can be
      def table_alias_length
        255
      end

      # Truncates a table alias according to the limits of the current adapter.
      def table_alias_for(table_name)
        table_name[0..table_alias_length-1].gsub(/\./, '_')
      end

      # def tables(name = nil) end

      def table_exists?(table_name)
        tables.include?(table_name.to_s)
      end

      # Returns an array of indexes for the given table.
      # def indexes(table_name, name = nil) end

      # Returns an array of Column objects for the table specified by +table_name+.
      # See the concrete implementation for details on the expected parameter values.
      def columns(table_name, name = nil) end

      # Creates a new table with the name +table_name+. +table_name+ may either
      # be a String or a Symbol.
      #
      # There are two ways to work with +create_table+.  You can use the block
      # form or the regular form, like this:
      #
      # === Block form
      #  # create_table() passes a TableDefinition object to the block.
      #  # This form will not only create the table, but also columns for the
      #  # table.
      #  create_table(:suppliers) do |t|
      #    t.column :name, :string, :limit => 60
      #    # Other fields here
      #  end
      #
      # === Regular form
      #  # Creates a table called 'suppliers' with no columns.
      #  create_table(:suppliers)
      #  # Add a column to 'suppliers'.
      #  add_column(:suppliers, :name, :string, {:limit => 60})
      #
      # The +options+ hash can include the following keys:
      # [<tt>:id</tt>]
      #   Whether to automatically add a primary key column. Defaults to true.
      #   Join tables for +has_and_belongs_to_many+ should set <tt>:id => false</tt>.
      # [<tt>:primary_key</tt>]
      #   The name of the primary key, if one is to be added automatically.
      #   Defaults to +id+.
      # [<tt>:options</tt>]
      #   Any extra options you want appended to the table definition.
      # [<tt>:temporary</tt>]
      #   Make a temporary table.
      # [<tt>:force</tt>]
      #   Set to true to drop the table before creating it.
      #   Defaults to false.
      #
      # ===== Examples
      # ====== Add a backend specific option to the generated SQL (MySQL)
      #  create_table(:suppliers, :options => 'ENGINE=InnoDB DEFAULT CHARSET=utf8')
      # generates:
      #  CREATE TABLE suppliers (
      #    id int(11) DEFAULT NULL auto_increment PRIMARY KEY
      #  ) ENGINE=InnoDB DEFAULT CHARSET=utf8
      #
      # ====== Rename the primary key column
      #  create_table(:objects, :primary_key => 'guid') do |t|
      #    t.column :name, :string, :limit => 80
      #  end
      # generates:
      #  CREATE TABLE objects (
      #    guid int(11) DEFAULT NULL auto_increment PRIMARY KEY,
      #    name varchar(80)
      #  )
      #
      # ====== Do not add a primary key column
      #  create_table(:categories_suppliers, :id => false) do |t|
      #    t.column :category_id, :integer
      #    t.column :supplier_id, :integer
      #  end
      # generates:
      #  CREATE TABLE categories_suppliers (
      #    category_id int,
      #    supplier_id int
      #  )
      #
      # See also TableDefinition#column for details on how to create columns.
      def create_table(table_name, options = {})
        table_definition = TableDefinition.new(self)
        table_definition.primary_key(options[:primary_key] || Base.get_primary_key(table_name)) unless options[:id] == false

        yield table_definition

        if options[:force] && table_exists?(table_name)
          drop_table(table_name, options)
        end

        create_sql = "CREATE#{' TEMPORARY' if options[:temporary]} TABLE "
        create_sql << "#{quote_table_name(table_name)} ("
        create_sql << table_definition.to_sql
        create_sql << ") #{options[:options]}"
        execute create_sql
      end

      # A block for changing columns in +table+.
      #
      # === Example
      #  # change_table() yields a Table instance
      #  change_table(:suppliers) do |t|
      #    t.column :name, :string, :limit => 60
      #    # Other column alterations here
      #  end
      #
      # ===== Examples
      # ====== Add a column
      #  change_table(:suppliers) do |t|
      #    t.column :name, :string, :limit => 60
      #  end
      #
      # ====== Add 2 integer columns
      #  change_table(:suppliers) do |t|
      #    t.integer :width, :height, :null => false, :default => 0
      #  end
      #
      # ====== Add created_at/updated_at columns
      #  change_table(:suppliers) do |t|
      #    t.timestamps
      #  end
      #
      # ====== Add a foreign key column
      #  change_table(:suppliers) do |t|
      #    t.references :company
      #  end
      #
      # Creates a <tt>company_id(integer)</tt> column
      #
      # ====== Add a polymorphic foreign key column
      #  change_table(:suppliers) do |t|
      #    t.belongs_to :company, :polymorphic => true
      #  end
      #
      # Creates <tt>company_type(varchar)</tt> and <tt>company_id(integer)</tt> columns
      #
      # ====== Remove a column
      #  change_table(:suppliers) do |t|
      #    t.remove :company
      #  end
      #
      # ====== Remove several columns
      #  change_table(:suppliers) do |t|
      #    t.remove :company_id
      #    t.remove :width, :height
      #  end
      #
      # ====== Remove an index
      #  change_table(:suppliers) do |t|
      #    t.remove_index :company_id
      #  end
      #
      # See also Table for details on
      # all of the various column transformation
      def change_table(table_name)
        yield Table.new(table_name, self)
      end

      # Renames a table.
      # ===== Example
      #  rename_table('octopuses', 'octopi')
      def rename_table(table_name, new_name)
        raise NotImplementedError, "rename_table is not implemented"
      end

      # Drops a table from the database.
      def drop_table(table_name, options = {})
        execute "DROP TABLE #{quote_table_name(table_name)}"
      end

      # Adds a new column to the named table.
      # See TableDefinition#column for details of the options you can use.
      def add_column(table_name, column_name, type, options = {})
        add_column_sql = "ALTER TABLE #{quote_table_name(table_name)} ADD #{quote_column_name(column_name)} #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}"
        add_column_options!(add_column_sql, options)
        execute(add_column_sql)
      end

      # Removes the column(s) from the table definition.
      # ===== Examples
      #  remove_column(:suppliers, :qualification)
      #  remove_columns(:suppliers, :qualification, :experience)
      def remove_column(table_name, *column_names)
        column_names.flatten.each do |column_name|
          execute "ALTER TABLE #{quote_table_name(table_name)} DROP #{quote_column_name(column_name)}"
        end
      end
      alias :remove_columns :remove_column

      # Changes the column's definition according to the new options.
      # See TableDefinition#column for details of the options you can use.
      # ===== Examples
      #  change_column(:suppliers, :name, :string, :limit => 80)
      #  change_column(:accounts, :description, :text)
      def change_column(table_name, column_name, type, options = {})
        raise NotImplementedError, "change_column is not implemented"
      end

      # Sets a new default value for a column.  If you want to set the default
      # value to +NULL+, you are out of luck.  You need to
      # DatabaseStatements#execute the appropriate SQL statement yourself.
      # ===== Examples
      #  change_column_default(:suppliers, :qualification, 'new')
      #  change_column_default(:accounts, :authorized, 1)
      def change_column_default(table_name, column_name, default)
        raise NotImplementedError, "change_column_default is not implemented"
      end

      # Renames a column.
      # ===== Example
      #  rename_column(:suppliers, :description, :name)
      def rename_column(table_name, column_name, new_column_name)
        raise NotImplementedError, "rename_column is not implemented"
      end

      # Adds a new index to the table.  +column_name+ can be a single Symbol, or
      # an Array of Symbols.
      #
      # The index will be named after the table and the first column name,
      # unless you pass <tt>:name</tt> as an option.
      #
      # When creating an index on multiple columns, the first column is used as a name
      # for the index. For example, when you specify an index on two columns
      # [<tt>:first</tt>, <tt>:last</tt>], the DBMS creates an index for both columns as well as an
      # index for the first column <tt>:first</tt>. Using just the first name for this index
      # makes sense, because you will never have to create a singular index with this
      # name.
      #
      # ===== Examples
      # ====== Creating a simple index
      #  add_index(:suppliers, :name)
      # generates
      #  CREATE INDEX suppliers_name_index ON suppliers(name)
      # ====== Creating a unique index
      #  add_index(:accounts, [:branch_id, :party_id], :unique => true)
      # generates
      #  CREATE UNIQUE INDEX accounts_branch_id_party_id_index ON accounts(branch_id, party_id)
      # ====== Creating a named index
      #  add_index(:accounts, [:branch_id, :party_id], :unique => true, :name => 'by_branch_party')
      # generates
      #  CREATE UNIQUE INDEX by_branch_party ON accounts(branch_id, party_id)
      def add_index(table_name, column_name, options = {})
        column_names = Array(column_name)
        index_name   = index_name(table_name, :column => column_names)

        if Hash === options # legacy support, since this param was a string
          index_type = options[:unique] ? "UNIQUE" : ""
          index_name = options[:name] || index_name
        else
          index_type = options
        end
        quoted_column_names = column_names.map { |e| quote_column_name(e) }.join(", ")
        execute "CREATE #{index_type} INDEX #{quote_column_name(index_name)} ON #{quote_table_name(table_name)} (#{quoted_column_names})"
      end

      # Remove the given index from the table.
      #
      # Remove the suppliers_name_index in the suppliers table.
      #   remove_index :suppliers, :name
      # Remove the index named accounts_branch_id_index in the accounts table.
      #   remove_index :accounts, :column => :branch_id
      # Remove the index named accounts_branch_id_party_id_index in the accounts table.
      #   remove_index :accounts, :column => [:branch_id, :party_id]
      # Remove the index named by_branch_party in the accounts table.
      #   remove_index :accounts, :name => :by_branch_party
      def remove_index(table_name, options = {})
        execute "DROP INDEX #{quote_column_name(index_name(table_name, options))} ON #{table_name}"
      end

      def index_name(table_name, options) #:nodoc:
        if Hash === options # legacy support
          if options[:column]
            "index_#{table_name}_on_#{Array(options[:column]) * '_and_'}"
          elsif options[:name]
            options[:name]
          else
            raise ArgumentError, "You must specify the index name"
          end
        else
          index_name(table_name, :column => options)
        end
      end

      # Returns a string of <tt>CREATE TABLE</tt> SQL statement(s) for recreating the
      # entire structure of the database.
      def structure_dump
      end

      def dump_schema_information #:nodoc:
        sm_table = ActiveRecord::Migrator.schema_migrations_table_name
        migrated = select_values("SELECT version FROM #{sm_table}")
        migrated.map { |v| "INSERT INTO #{sm_table} (version) VALUES ('#{v}');" }.join("\n\n")
      end

      # Should not be called normally, but this operation is non-destructive.
      # The migrations module handles this automatically.
      def initialize_schema_migrations_table
        sm_table = ActiveRecord::Migrator.schema_migrations_table_name

        unless tables.detect { |t| t == sm_table }
          create_table(sm_table, :id => false) do |schema_migrations_table|
            schema_migrations_table.column :version, :string, :null => false
          end
          add_index sm_table, :version, :unique => true,
            :name => 'unique_schema_migrations'

          # Backwards-compatibility: if we find schema_info, assume we've
          # migrated up to that point:
          si_table = Base.table_name_prefix + 'schema_info' + Base.table_name_suffix

          if tables.detect { |t| t == si_table }

            old_version = select_value("SELECT version FROM #{quote_table_name(si_table)}").to_i
            assume_migrated_upto_version(old_version)
            drop_table(si_table)
          end
        end
      end

      def assume_migrated_upto_version(version)
        version = version.to_i
        sm_table = quote_table_name(ActiveRecord::Migrator.schema_migrations_table_name)

        migrated = select_values("SELECT version FROM #{sm_table}").map(&:to_i)
        versions = Dir['db/migrate/[0-9]*_*.rb'].map do |filename|
          filename.split('/').last.split('_').first.to_i
        end

        unless migrated.include?(version)
          execute "INSERT INTO #{sm_table} (version) VALUES ('#{version}')"
        end

        inserted = Set.new
        (versions - migrated).each do |v|
          if inserted.include?(v)
            raise "Duplicate migration #{v}. Please renumber your migrations to resolve the conflict."
          elsif v < version
            execute "INSERT INTO #{sm_table} (version) VALUES ('#{v}')"
            inserted << v
          end
        end
      end

      def type_to_sql(type, limit = nil, precision = nil, scale = nil) #:nodoc:
        if native = native_database_types[type]
          column_type_sql = (native.is_a?(Hash) ? native[:name] : native).dup

          if type == :decimal # ignore limit, use precision and scale
            scale ||= native[:scale]

            if precision ||= native[:precision]
              if scale
                column_type_sql << "(#{precision},#{scale})"
              else
                column_type_sql << "(#{precision})"
              end
            elsif scale
              raise ArgumentError, "Error adding decimal column: precision cannot be empty if scale if specified"
            end

          elsif (type != :primary_key) && (limit ||= native.is_a?(Hash) && native[:limit])
            column_type_sql << "(#{limit})"
          end

          column_type_sql
        else
          type
        end
      end

      def add_column_options!(sql, options) #:nodoc:
        sql << " DEFAULT #{quote(options[:default], options[:column])}" if options_include_default?(options)
        # must explicitly check for :null to allow change_column to work on migrations
        if options[:null] == false
          sql << " NOT NULL"
        end
      end

      # SELECT DISTINCT clause for a given set of columns and a given ORDER BY clause.
      # Both PostgreSQL and Oracle overrides this for custom DISTINCT syntax.
      #
      #   distinct("posts.id", "posts.created_at desc")
      def distinct(columns, order_by)
        "DISTINCT #{columns}"
      end

      # ORDER BY clause for the passed order option.
      # PostgreSQL overrides this due to its stricter standards compliance.
      def add_order_by_for_association_limiting!(sql, options)
        sql << " ORDER BY #{options[:order]}"
      end

      # Adds timestamps (created_at and updated_at) columns to the named table.
      # ===== Examples
      #  add_timestamps(:suppliers)
      def add_timestamps(table_name)
        add_column table_name, :created_at, :datetime
        add_column table_name, :updated_at, :datetime
      end

      # Removes the timestamp columns (created_at and updated_at) from the table definition.
      # ===== Examples
      #  remove_timestamps(:suppliers)
      def remove_timestamps(table_name)
        remove_column table_name, :updated_at
        remove_column table_name, :created_at
      end

      protected
        def options_include_default?(options)
          options.include?(:default) && !(options[:null] == false && options[:default].nil?)
        end
    end
  end
end