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Sequel::Schema::Generator

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.

Constants

GENERIC_TYPES

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_type_method(*types) click to toggle source

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.

    # 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
new(db, &block) click to toggle source

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

    # 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

check(*args, &block) click to toggle source

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
    # File lib/sequel/database/schema_generator.rb, line 58
58:       def check(*args, &block)
59:         constraint(nil, *args, &block)
60:       end
column(name, type, opts = {}) click to toggle source

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.

     # 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
constraint(name, *args, &block) click to toggle source

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
     # 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_columns() click to toggle source

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

     # File lib/sequel/extensions/schema_dumper.rb, line 384
384:       def dump_columns
385:         strings = []
386:         cols = columns.dup
387:         cols.each do |x|
388:           x.delete(:on_delete) if x[:on_delete] == :no_action
389:           x.delete(:on_update) if x[:on_update] == :no_action
390:         end
391:         if pkn = primary_key_name
392:           cols.delete_if{|x| x[:name] == pkn}
393:           pk = @primary_key.dup
394:           pkname = pk.delete(:name)
395:           @db.serial_primary_key_options.each{|k,v| pk.delete(k) if v == pk[k]}
396:           strings << "primary_key #{pkname.inspect}#{opts_inspect(pk)}"
397:         end
398:         cols.each do |c|
399:           c = c.dup
400:           name = c.delete(:name)
401:           strings << if table = c.delete(:table)
402:             c.delete(:type) if c[:type] == Integer || c[:type] == 'integer'
403:             "foreign_key #{name.inspect}, #{table.inspect}#{opts_inspect(c)}"
404:           else
405:             type = c.delete(:type)
406:             opts = opts_inspect(c)
407:             if type.is_a?(Class)
408:               "#{type.name} #{name.inspect}#{opts}"
409:             else
410:               "column #{name.inspect}, #{type.inspect}#{opts}"
411:             end
412:           end
413:         end
414:         strings.join("\n")
415:       end
dump_constraints() click to toggle source

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

     # File lib/sequel/extensions/schema_dumper.rb, line 419
419:       def dump_constraints
420:         cs = constraints.map do |c|
421:           c = c.dup
422:           type = c.delete(:type)
423:           case type
424:           when :check
425:             raise(Error, "can't dump check/constraint specified with Proc") if c[:check].is_a?(Proc)
426:             name = c.delete(:name)
427:             if !name and c[:check].length == 1 and c[:check].first.is_a?(Hash)
428:               "check #{c[:check].first.inspect[1...-1]}"
429:             else
430:               "#{name ? "constraint #{name.inspect}," : 'check'} #{c[:check].map{|x| x.inspect}.join(', ')}"
431:             end
432:           when :foreign_key
433:             c.delete(:on_delete) if c[:on_delete] == :no_action
434:             c.delete(:on_update) if c[:on_update] == :no_action
435:             c.delete(:deferrable) unless c[:deferrable]
436:             cols = c.delete(:columns)
437:             table = c.delete(:table)
438:             "#{type} #{cols.inspect}, #{table.inspect}#{opts_inspect(c)}"
439:           else
440:             cols = c.delete(:columns)
441:             "#{type} #{cols.inspect}#{opts_inspect(c)}"
442:           end
443:         end
444:         cs.join("\n")
445:       end
dump_indexes(options={}) click to toggle source

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

     # File lib/sequel/extensions/schema_dumper.rb, line 454
454:       def dump_indexes(options={})
455:         is = indexes.map do |c|
456:           c = c.dup
457:           cols = c.delete(:columns)
458:           if table = options[:add_index] || options[:drop_index]
459:             "#{options[:drop_index] ? 'drop' : 'add'}_index #{table.inspect}, #{cols.inspect}#{', :ignore_errors=>true' if options[:ignore_errors]}#{opts_inspect(c)}"
460:           else
461:             "index #{cols.inspect}#{opts_inspect(c)}"
462:           end
463:         end
464:         is = is.reverse if options[:drop_index]
465:         is.join("\n")
466:       end
foreign_key(name, table=nil, opts = {}) click to toggle source

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
     # 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
full_text_index(columns, opts = {}) click to toggle source

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.

     # 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
has_column?(name) click to toggle source

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

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

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)
     # File lib/sequel/database/schema_generator.rb, line 189
189:       def index(columns, opts = {})
190:         indexes << {:columns => Array(columns)}.merge(opts)
191:       end
method_missing(type, name = nil, opts = {}) click to toggle source

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

     # 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
primary_key(name, *args) click to toggle source

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])
     # 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
primary_key_name() click to toggle source

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

     # File lib/sequel/database/schema_generator.rb, line 227
227:       def primary_key_name
228:         @primary_key[:name] if @primary_key
229:       end
spatial_index(columns, opts = {}) click to toggle source

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

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

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

  unique(:name) # UNIQUE (name)
     # 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

Private Instance Methods

composite_foreign_key(columns, opts) click to toggle source

Add a composite foreign key constraint

     # File lib/sequel/database/schema_generator.rb, line 252
252:       def composite_foreign_key(columns, opts)
253:         constraints << {:type => :foreign_key, :columns => columns}.merge(opts)
254:       end
composite_primary_key(columns, *args) click to toggle source

Add a composite primary key constraint

     # File lib/sequel/database/schema_generator.rb, line 246
246:       def composite_primary_key(columns, *args)
247:         opts = args.pop || {}
248:         constraints << {:type => :primary_key, :columns => columns}.merge(opts)
249:       end
opts_inspect(opts) click to toggle source

Return a string that converts the given options into one suitable for literal ruby code, handling default values that don’t default to a literal interpretation.

     # File lib/sequel/extensions/schema_dumper.rb, line 473
473:       def opts_inspect(opts)
474:         if opts[:default]
475:           opts = opts.dup
476:           de = case d = opts.delete(:default)
477:           when BigDecimal, Sequel::SQL::Blob
478:             "#{d.class.name}.new(#{d.to_s.inspect})"
479:           when DateTime, Date
480:             "#{d.class.name}.parse(#{d.to_s.inspect})"
481:           when Time
482:             "#{d.class.name}.parse(#{d.strftime('%H:%M:%S').inspect})"
483:           else
484:             d.inspect
485:           end
486:           ", :default=>#{de}#{", #{opts.inspect[1...-1]}" if opts.length > 0}"
487:         else
488:           ", #{opts.inspect[1...-1]}" if opts.length > 0
489:         end
490:       end

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