Class Sequel::Schema::Generator
In: lib/sequel/database/schema_generator.rb
lib/sequel/extensions/schema_dumper.rb
Parent: Object

Schema::Generator is an internal class that the user is not expected to instantiate directly. Instances are created by Database#create_table. It is used to specify table creation parameters. It takes a Database object and a block of column/index/constraint specifications, and gives the Database a table description, which the database uses to create a table.

Schema::Generator has some methods but also includes method_missing, allowing users to specify column type as a method instead of using the column method, which makes for a nicer DSL.

For more information on Sequel‘s support for schema modification, see the "Migrations and Schema Modification" guide.

Methods

Constants

GENERIC_TYPES = [String, Integer, Fixnum, Bignum, Float, Numeric, BigDecimal, Date, DateTime, Time, File, TrueClass, FalseClass]   Classes specifying generic types that Sequel will convert to database-specific types.

Attributes

columns  [R]  Return the column hashes created by this generator
constraints  [R]  Return the constraint hashes created by this generator
indexes  [R]  Return the index hashes created by this generator

Public Class methods

Add a method for each of the given types that creates a column with that type as a constant. Types given should either already be constants/classes or a capitalized string/symbol with the same name as a constant/class.

[Source]

    # File lib/sequel/database/schema_generator.rb, line 47
47:       def self.add_type_method(*types)
48:         types.each do |type|
49:           class_eval("def #{type}(name, opts={}); column(name, #{type}, opts); end", __FILE__, __LINE__)
50:         end
51:       end

Set the database in which to create the table, and evaluate the block in the context of this object.

[Source]

    # File lib/sequel/database/schema_generator.rb, line 33
33:       def initialize(db, &block)
34:         @db = db
35:         @columns = []
36:         @indexes = []
37:         @constraints = []
38:         @primary_key = nil
39:         instance_eval(&block) if block
40:         @columns.unshift(@primary_key) if @primary_key && !has_column?(primary_key_name)
41:       end

Public Instance methods

Add an unnamed constraint to the DDL, specified by the given block or args:

  check(:num=>1..5) # CHECK num >= 1 AND num <= 5
  check{num > 5} # CHECK num > 5

[Source]

    # File lib/sequel/database/schema_generator.rb, line 58
58:       def check(*args, &block)
59:         constraint(nil, *args, &block)
60:       end

Add a column with the given name, type, and opts to the DDL.

  column :num, :integer
  # num INTEGER

  column :name, String, :null=>false, :default=>'a'
  # name varchar(255) NOT NULL DEFAULT 'a'

  inet :ip
  # ip inet

You can also create columns via method missing, so the following are equivalent:

  column :number, :integer
  integer :number

The following options are supported:

:default :The default value for the column.
:deferrable :This ensure Referential Integrity will work even if reference table will use for its foreign key a value that does not exists(yet) on referenced table. Basically it adds DEFERRABLE INITIALLY DEFERRED on key creation.
:index :Create an index on this column. If given a hash, use the hash as the options for the index.
:key :For foreign key columns, the column in the associated table that this column references. Unnecessary if this column references the primary key of the associated table, except if you are using MySQL.
:null :Mark the column as allowing NULL values (if true), or not allowing NULL values (if false). If unspecified, will default to whatever the database default is.
:on_delete :Specify the behavior of this column when being deleted (:restrict, :cascade, :set_null, :set_default, :no_action).
:on_update :Specify the behavior of this column when being updated (:restrict, :cascade, :set_null, :set_default, :no_action).
:primary_key :Make the column as a single primary key column. This should only be used if you have a single, nonautoincrementing primary key column.
:unique :Mark the column as unique, generally has the same effect as creating a unique index on the column.

[Source]

     # File lib/sequel/database/schema_generator.rb, line 103
103:       def column(name, type, opts = {})
104:         columns << {:name => name, :type => type}.merge(opts)
105:         if index_opts = opts[:index]
106:           index(name, index_opts.is_a?(Hash) ? index_opts : {})
107:         end
108:       end

Adds a named constraint (or unnamed if name is nil) to the DDL, with the given block or args.

  constraint(:blah, :num=>1..5) # CONSTRAINT blah CHECK num >= 1 AND num <= 5
  check(:foo){num > 5} # CONSTRAINT foo CHECK num > 5

[Source]

     # File lib/sequel/database/schema_generator.rb, line 115
115:       def constraint(name, *args, &block)
116:         constraints << {:name => name, :type => :check, :check => block || args}
117:       end

Dump this generator‘s columns to a string that could be evaled inside another instance to represent the same columns

[Source]

     # File lib/sequel/extensions/schema_dumper.rb, line 387
387:       def dump_columns
388:         strings = []
389:         cols = columns.dup
390:         cols.each do |x|
391:           x.delete(:on_delete) if x[:on_delete] == :no_action
392:           x.delete(:on_update) if x[:on_update] == :no_action
393:         end
394:         if pkn = primary_key_name
395:           cols.delete_if{|x| x[:name] == pkn}
396:           pk = @primary_key.dup
397:           pkname = pk.delete(:name)
398:           @db.serial_primary_key_options.each{|k,v| pk.delete(k) if v == pk[k]}
399:           strings << "primary_key #{pkname.inspect}#{opts_inspect(pk)}"
400:         end
401:         cols.each do |c|
402:           c = c.dup
403:           name = c.delete(:name)
404:           strings << if table = c.delete(:table)
405:             c.delete(:type) if c[:type] == Integer || c[:type] == 'integer'
406:             "foreign_key #{name.inspect}, #{table.inspect}#{opts_inspect(c)}"
407:           else
408:             type = c.delete(:type)
409:             opts = opts_inspect(c)
410:             if type.is_a?(Class)
411:               "#{type.name} #{name.inspect}#{opts}"
412:             else
413:               "column #{name.inspect}, #{type.inspect}#{opts}"
414:             end
415:           end
416:         end
417:         strings.join("\n")
418:       end

Dump this generator‘s constraints to a string that could be evaled inside another instance to represent the same constraints

[Source]

     # File lib/sequel/extensions/schema_dumper.rb, line 422
422:       def dump_constraints
423:         cs = constraints.map do |c|
424:           c = c.dup
425:           type = c.delete(:type)
426:           case type
427:           when :check
428:             raise(Error, "can't dump check/constraint specified with Proc") if c[:check].is_a?(Proc)
429:             name = c.delete(:name)
430:             if !name and c[:check].length == 1 and c[:check].first.is_a?(Hash)
431:               "check #{c[:check].first.inspect[1...-1]}"
432:             else
433:               "#{name ? "constraint #{name.inspect}," : 'check'} #{c[:check].map{|x| x.inspect}.join(', ')}"
434:             end
435:           when :foreign_key
436:             c.delete(:on_delete) if c[:on_delete] == :no_action
437:             c.delete(:on_update) if c[:on_update] == :no_action
438:             c.delete(:deferrable) unless c[:deferrable]
439:             cols = c.delete(:columns)
440:             table = c.delete(:table)
441:             "#{type} #{cols.inspect}, #{table.inspect}#{opts_inspect(c)}"
442:           else
443:             cols = c.delete(:columns)
444:             "#{type} #{cols.inspect}#{opts_inspect(c)}"
445:           end
446:         end
447:         cs.join("\n")
448:       end

Dump this generator‘s indexes to a string that could be evaled inside another instance to represent the same indexes. Options:

  • :add_index - Use add_index instead of index, so the methods can be called outside of a generator but inside a migration. The value of this option should be the table name to use.
  • :drop_index - Same as add_index, but create drop_index statements.
  • :ignore_errors - Add the ignore_errors option to the outputted indexes

[Source]

     # File lib/sequel/extensions/schema_dumper.rb, line 457
457:       def dump_indexes(options={})
458:         is = indexes.map do |c|
459:           c = c.dup
460:           cols = c.delete(:columns)
461:           if table = options[:add_index] || options[:drop_index]
462:             "#{options[:drop_index] ? 'drop' : 'add'}_index #{table.inspect}, #{cols.inspect}#{', :ignore_errors=>true' if options[:ignore_errors]}#{opts_inspect(c)}"
463:           else
464:             "index #{cols.inspect}#{opts_inspect(c)}"
465:           end
466:         end
467:         is = is.reverse if options[:drop_index]
468:         is.join("\n")
469:       end

Add a foreign key in the table that references another table to the DDL. See column for available options.

  foreign_key(:artist_id) # artist_id INTEGER
  foreign_key(:artist_id, :artists) # artist_id INTEGER REFERENCES artists
  foreign_key(:artist_id, :artists, :key=>:id) # artist_id INTEGER REFERENCES artists(id)

If you want a foreign key constraint without adding a column (usually because it is a composite foreign key), you can provide an array of columns as the first argument, and you can provide the :name option to name the constraint:

  foreign_key([:artist_name, :artist_location], :artists, :name=>:artist_fk)
  # ADD CONSTRAINT artist_fk FOREIGN KEY (artist_name, artist_location) REFERENCES artists

[Source]

     # File lib/sequel/database/schema_generator.rb, line 132
132:       def foreign_key(name, table=nil, opts = {})
133:         opts = case table
134:         when Hash
135:           table.merge(opts)
136:         when Symbol
137:           opts.merge(:table=>table)
138:         when NilClass
139:           opts
140:         else
141:           raise(Error, "The second argument to foreign_key should be a Hash, Symbol, or nil")
142:         end
143:         return composite_foreign_key(name, opts) if name.is_a?(Array)
144:         column(name, Integer, opts)
145:       end

Add a full text index on the given columns to the DDL.

PostgreSQL specific options:

:language :Set a language to use for the index (default: simple).

Microsoft SQL Server specific options:

:key_index :The KEY INDEX to use for the full text index.

[Source]

     # File lib/sequel/database/schema_generator.rb, line 154
154:       def full_text_index(columns, opts = {})
155:         index(columns, opts.merge(:type => :full_text))
156:       end

True if the DDL includes the creation of a column with the given name.

[Source]

     # File lib/sequel/database/schema_generator.rb, line 159
159:       def has_column?(name)
160:         columns.any?{|c| c[:name] == name}
161:       end

Add an index on the given column(s) with the given options to the DDL. General options:

:name :The name to use for the index. If not given, a default name based on the table and columns is used.
:type :The type of index to use (only supported by some databases)
:unique :Make the index unique, so duplicate values are not allowed.
:where :Create a partial index (only supported by some databases)

PostgreSQL specific options:

:concurrently :Create the index concurrently, so it doesn‘t block operations on the table while the index is being built.
:op_class :Use a specific operator class in the index.

Microsoft SQL Server specific options:

:include :Include additional column values in the index, without actually indexing on those values.
  index :name
  # CREATE INDEX table_name_index ON table (name)

  index [:artist_id, :name]
  # CREATE INDEX table_artist_id_name_index ON table (artist_id, name)

[Source]

     # File lib/sequel/database/schema_generator.rb, line 189
189:       def index(columns, opts = {})
190:         indexes << {:columns => Array(columns)}.merge(opts)
191:       end

Add a column with the given type, name, and opts to the DDL. See column for available options.

[Source]

     # File lib/sequel/database/schema_generator.rb, line 195
195:       def method_missing(type, name = nil, opts = {})
196:         name ? column(name, type, opts) : super
197:       end

Adds an autoincrementing primary key column or a primary key constraint to the DDL. To create a constraint, the first argument should be an array of column symbols specifying the primary key columns. To create an autoincrementing primary key column, a single symbol can be used. In both cases, an options hash can be used as the second argument.

If you want to create a primary key column that is not autoincrementing, you should not use this method. Instead, you should use the regular column method with a :primary_key=>true option.

Examples:

  primary_key(:id)
  primary_key([:street_number, :house_number])

[Source]

     # File lib/sequel/database/schema_generator.rb, line 212
212:       def primary_key(name, *args)
213:         return composite_primary_key(name, *args) if name.is_a?(Array)
214:         @primary_key = @db.serial_primary_key_options.merge({:name => name})
215:         
216:         if opts = args.pop
217:           opts = {:type => opts} unless opts.is_a?(Hash)
218:           if type = args.pop
219:             opts.merge!(:type => type)
220:           end
221:           @primary_key.merge!(opts)
222:         end
223:         @primary_key
224:       end

The name of the primary key for this generator, if it has a primary key.

[Source]

     # File lib/sequel/database/schema_generator.rb, line 227
227:       def primary_key_name
228:         @primary_key[:name] if @primary_key
229:       end

Add a spatial index on the given columns to the DDL.

[Source]

     # File lib/sequel/database/schema_generator.rb, line 232
232:       def spatial_index(columns, opts = {})
233:         index(columns, opts.merge(:type => :spatial))
234:       end

Add a unique constraint on the given columns to the DDL.

  unique(:name) # UNIQUE (name)

[Source]

     # File lib/sequel/database/schema_generator.rb, line 239
239:       def unique(columns, opts = {})
240:         constraints << {:type => :unique, :columns => Array(columns)}.merge(opts)
241:       end

[Validate]