Class Sequel::Schema::Generator
In: lib/sequel/extensions/schema_dumper.rb
lib/sequel/database/schema_generator.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.
: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.
:size :The size of the column, generally used with string columns to specify the maximum number of characters the column will hold. An array of two integers can be provided to set the size and the precision, respectively, of decimal columns.
:unique :Mark the column as unique, generally has the same effect as creating a unique index on the column.
:unsigned :Make the column type unsigned, only useful for integer columns.

[Source]

     # File lib/sequel/database/schema_generator.rb, line 108
108:       def column(name, type, opts = {})
109:         columns << {:name => name, :type => type}.merge(opts)
110:         index(name) if opts[:index]
111:       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 118
118:       def constraint(name, *args, &block)
119:         constraints << {:name => name, :type => :check, :check => block || args}
120:       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 192
192:       def dump_columns
193:         strings = []
194:         cols = columns.dup
195:         if pkn = primary_key_name
196:           cols.delete_if{|x| x[:name] == pkn}
197:           pk = @primary_key.dup
198:           pkname = pk.delete(:name)
199:           @db.serial_primary_key_options.each{|k,v| pk.delete(k) if v == pk[k]}
200:           strings << "primary_key #{pkname.inspect}#{opts_inspect(pk)}"
201:         end
202:         cols.each do |c|
203:           c = c.dup
204:           name = c.delete(:name)
205:           type = c.delete(:type)
206:           opts = opts_inspect(c)
207:           strings << if type.is_a?(Class)
208:             "#{type.name} #{name.inspect}#{opts}"
209:           else
210:             "column #{name.inspect}, #{type.inspect}#{opts}"
211:           end
212:         end
213:         strings.join("\n")
214:       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 218
218:       def dump_constraints
219:         cs = constraints.map do |c|
220:           c = c.dup
221:           type = c.delete(:type)
222:           case type
223:           when :check
224:             raise(Error, "can't dump check/constraint specified with Proc") if c[:check].is_a?(Proc)
225:             name = c.delete(:name)
226:             if !name and c[:check].length == 1 and c[:check].first.is_a?(Hash)
227:               "check #{c[:check].first.inspect[1...-1]}"
228:             else
229:               "#{name ? "constraint #{name.inspect}," : 'check'} #{c[:check].map{|x| x.inspect}.join(', ')}"
230:             end
231:           else
232:             cols = c.delete(:columns)
233:             "#{type} #{cols.inspect}#{opts_inspect(c)}"
234:           end
235:         end
236:         cs.join("\n")
237:       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 246
246:       def dump_indexes(options={})
247:         is = indexes.map do |c|
248:           c = c.dup
249:           cols = c.delete(:columns)
250:           if table = options[:add_index] || options[:drop_index]
251:             "#{options[:drop_index] ? 'drop' : 'add'}_index #{table.inspect}, #{cols.inspect}#{', :ignore_errors=>true' if options[:ignore_errors]}#{opts_inspect(c)}"
252:           else
253:             "index #{cols.inspect}#{opts_inspect(c)}"
254:           end
255:         end
256:         is.join("\n")
257:       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 135
135:       def foreign_key(name, table=nil, opts = {})
136:         opts = case table
137:         when Hash
138:           table.merge(opts)
139:         when Symbol
140:           opts.merge(:table=>table)
141:         when NilClass
142:           opts
143:         else
144:           raise(Error, "The second argument to foreign_key should be a Hash, Symbol, or nil")
145:         end
146:         return composite_foreign_key(name, opts) if name.is_a?(Array)
147:         column(name, Integer, opts)
148:       end

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

[Source]

     # File lib/sequel/database/schema_generator.rb, line 151
151:       def full_text_index(columns, opts = {})
152:         index(columns, opts.merge(:type => :full_text))
153:       end

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

[Source]

     # File lib/sequel/database/schema_generator.rb, line 156
156:       def has_column?(name)
157:         columns.any?{|c| c[:name] == name}
158:       end

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

: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)
  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 172
172:       def index(columns, opts = {})
173:         indexes << {:columns => Array(columns)}.merge(opts)
174:       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 178
178:       def method_missing(type, name = nil, opts = {})
179:         name ? column(name, type, opts) : super
180:       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 195
195:       def primary_key(name, *args)
196:         return composite_primary_key(name, *args) if name.is_a?(Array)
197:         @primary_key = @db.serial_primary_key_options.merge({:name => name})
198:         
199:         if opts = args.pop
200:           opts = {:type => opts} unless opts.is_a?(Hash)
201:           if type = args.pop
202:             opts.merge!(:type => type)
203:           end
204:           @primary_key.merge!(opts)
205:         end
206:         @primary_key
207:       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 210
210:       def primary_key_name
211:         @primary_key[:name] if @primary_key
212:       end

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

[Source]

     # File lib/sequel/database/schema_generator.rb, line 215
215:       def spatial_index(columns, opts = {})
216:         index(columns, opts.merge(:type => :spatial))
217:       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 222
222:       def unique(columns, opts = {})
223:         constraints << {:type => :unique, :columns => Array(columns)}.merge(opts)
224:       end

[Validate]