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.

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 columns created by this generator
constraints  [R]  Return the constraints created by this generator
indexes  [R]  Return the indexes 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 45
45:       def self.add_type_method(*types)
46:         types.each do |type|
47:           class_eval("def #{type}(name, opts={}); column(name, #{type}, opts); end", __FILE__, __LINE__)
48:         end
49:       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 31
31:       def initialize(db, &block)
32:         @db = db
33:         @columns = []
34:         @indexes = []
35:         @constraints = []
36:         @primary_key = nil
37:         instance_eval(&block) if block
38:         @columns.unshift(@primary_key) if @primary_key && !has_column?(primary_key_name)
39:       end

Public Instance methods

Add a unnamed constraint to the DDL, specified by the given block or args.

[Source]

    # File lib/sequel/database/schema_generator.rb, line 53
53:       def check(*args, &block)
54:         constraint(nil, *args, &block)
55:       end

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

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.
  • :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.
  • :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. See Dataset#on_delete_clause for options.
  • :on_update - Specify the behavior of this column when being updated. See Schema::SQL#on_delete_clause for options.
  • :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 87
87:       def column(name, type, opts = {})
88:         columns << {:name => name, :type => type}.merge(opts)
89:         index(name) if opts[:index]
90:       end

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

[Source]

    # File lib/sequel/database/schema_generator.rb, line 94
94:       def constraint(name, *args, &block)
95:         constraints << {:name => name, :type => :check, :check => block || args}
96:       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 182
182:       def dump_columns
183:         strings = []
184:         cols = columns.dup
185:         if pkn = primary_key_name
186:           cols.delete_if{|x| x[:name] == pkn}
187:           pk = @primary_key.dup
188:           pkname = pk.delete(:name)
189:           @db.serial_primary_key_options.each{|k,v| pk.delete(k) if v == pk[k]}
190:           strings << "primary_key #{pkname.inspect}#{opts_inspect(pk)}"
191:         end
192:         cols.each do |c|
193:           c = c.dup
194:           name = c.delete(:name)
195:           type = c.delete(:type)
196:           opts = opts_inspect(c)
197:           strings << if type.is_a?(Class)
198:             "#{type.name} #{name.inspect}#{opts}"
199:           else
200:             "column #{name.inspect}, #{type.inspect}#{opts}"
201:           end
202:         end
203:         strings.join("\n")
204:       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 208
208:       def dump_constraints
209:         constraints.map do |c|
210:           c = c.dup
211:           type = c.delete(:type)
212:           case type
213:           when :check
214:             raise(Error, "can't dump check/constraint specified with Proc") if c[:check].is_a?(Proc)
215:             name = c.delete(:name)
216:             if !name and c[:check].length == 1 and c[:check].first.is_a?(Hash)
217:               "check #{c[:check].first.inspect[1...-1]}"
218:             else
219:               "#{name ? "constraint #{name.inspect}," : 'check'} #{c[:check].map{|x| x.inspect}.join(', ')}"
220:             end
221:           else
222:             cols = c.delete(:columns)
223:             "#{type} #{cols.inspect}#{opts_inspect(c)}"
224:           end
225:         end.join("\n")
226:       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 235
235:       def dump_indexes(options={})
236:         indexes.map do |c|
237:           c = c.dup
238:           cols = c.delete(:columns)
239:           if table = options[:add_index] || options[:drop_index]
240:             "#{options[:drop_index] ? 'drop' : 'add'}_index #{table.inspect}, #{cols.inspect}#{', :ignore_errors=>true' if options[:ignore_errors]}#{opts_inspect(c)}"
241:           else
242:             "index #{cols.inspect}#{opts_inspect(c)}"
243:           end
244:         end.join("\n")
245:       end

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

[Source]

     # File lib/sequel/database/schema_generator.rb, line 100
100:       def foreign_key(name, table=nil, opts = {})
101:         opts = case table
102:         when Hash
103:           table.merge(opts)
104:         when Symbol
105:           opts.merge(:table=>table)
106:         when NilClass
107:           opts
108:         else
109:           raise(Error, "The second argument to foreign_key should be a Hash, Symbol, or nil")
110:         end
111:         return composite_foreign_key(name, opts) if name.is_a?(Array)
112:         column(name, Integer, opts)
113:       end

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

[Source]

     # File lib/sequel/database/schema_generator.rb, line 116
116:       def full_text_index(columns, opts = {})
117:         index(columns, opts.merge(:type => :full_text))
118:       end

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

[Source]

     # File lib/sequel/database/schema_generator.rb, line 121
121:       def has_column?(name)
122:         columns.any?{|c| c[:name] == name}
123:       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)

[Source]

     # File lib/sequel/database/schema_generator.rb, line 131
131:       def index(columns, opts = {})
132:         indexes << {:columns => Array(columns)}.merge(opts)
133:       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 137
137:       def method_missing(type, name = nil, opts = {})
138:         name ? column(name, type, opts) : super
139:       end

Add primary key information to the DDL. Takes between one and three arguments. The last one is an options hash as for Generator#column. The first one distinguishes two modes: an array of existing column names adds a composite primary key constraint. A single symbol adds a new column of that name and makes it the primary key. In that case the optional middle argument denotes the type.

Examples:

  primary_key(:id)
  primary_key(:zip_code, :null => false)
  primary_key([:street_number, :house_number])
  primary_key(:id, :string, :auto_increment => false)

[Source]

     # File lib/sequel/database/schema_generator.rb, line 153
153:       def primary_key(name, *args)
154:         return composite_primary_key(name, *args) if name.is_a?(Array)
155:         @primary_key = @db.serial_primary_key_options.merge({:name => name})
156:         
157:         if opts = args.pop
158:           opts = {:type => opts} unless opts.is_a?(Hash)
159:           if type = args.pop
160:             opts.merge!(:type => type)
161:           end
162:           @primary_key.merge!(opts)
163:         end
164:         @primary_key
165:       end

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

[Source]

     # File lib/sequel/database/schema_generator.rb, line 168
168:       def primary_key_name
169:         @primary_key[:name] if @primary_key
170:       end

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

[Source]

     # File lib/sequel/database/schema_generator.rb, line 173
173:       def spatial_index(columns, opts = {})
174:         index(columns, opts.merge(:type => :spatial))
175:       end

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

[Source]

     # File lib/sequel/database/schema_generator.rb, line 178
178:       def unique(columns, opts = {})
179:         constraints << {:type => :unique, :columns => Array(columns)}.merge(opts)
180:       end

[Validate]