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.
  • :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 85
85:       def column(name, type, opts = {})
86:         columns << {:name => name, :type => type}.merge(opts)
87:         index(name) if opts[:index]
88:       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 92
92:       def constraint(name, *args, &block)
93:         constraints << {:name => name, :type => :check, :check => block || args}
94:       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 176
176:       def dump_columns
177:         strings = []
178:         cols = columns.dup
179:         if pkn = primary_key_name
180:           cols.delete_if{|x| x[:name] == pkn}
181:           pk = @primary_key.dup
182:           pkname = pk.delete(:name)
183:           @db.serial_primary_key_options.each{|k,v| pk.delete(k) if v == pk[k]}
184:           strings << "primary_key #{pkname.inspect}#{opts_inspect(pk)}"
185:         end
186:         cols.each do |c|
187:           c = c.dup
188:           name = c.delete(:name)
189:           type = c.delete(:type)
190:           opts = opts_inspect(c)
191:           strings << if type.is_a?(Class)
192:             "#{type.name} #{name.inspect}#{opts}"
193:           else
194:             "column #{name.inspect}, #{type.inspect}#{opts}"
195:           end
196:         end
197:         strings.join("\n")
198:       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 202
202:       def dump_constraints
203:         constraints.map do |c|
204:           c = c.dup
205:           type = c.delete(:type)
206:           case type
207:           when :check
208:             raise(Error, "can't dump check/constraint specified with Proc") if c[:check].is_a?(Proc)
209:             name = c.delete(:name)
210:             if !name and c[:check].length == 1 and c[:check].first.is_a?(Hash)
211:               "check #{c[:check].first.inspect[1...-1]}"
212:             else
213:               "#{name ? "constraint #{name.inspect}," : 'check'} #{c[:check].map{|x| x.inspect}.join(', ')}"
214:             end
215:           else
216:             cols = c.delete(:columns)
217:             "#{type} #{cols.inspect}#{opts_inspect(c)}"
218:           end
219:         end.join("\n")
220:       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 229
229:       def dump_indexes(options={})
230:         indexes.map do |c|
231:           c = c.dup
232:           cols = c.delete(:columns)
233:           if table = options[:add_index] || options[:drop_index]
234:             "#{options[:drop_index] ? 'drop' : 'add'}_index #{table.inspect}, #{cols.inspect}#{', :ignore_errors=>true' if options[:ignore_errors]}#{opts_inspect(c)}"
235:           else
236:             "index #{cols.inspect}#{opts_inspect(c)}"
237:           end
238:         end.join("\n")
239:       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 98
 98:       def foreign_key(name, table=nil, opts = {})
 99:         opts = case table
100:         when Hash
101:           table.merge(opts)
102:         when Symbol
103:           opts.merge(:table=>table)
104:         when NilClass
105:           opts
106:         else
107:           raise(Error, "The second argument to foreign_key should be a Hash, Symbol, or nil")
108:         end
109:         return composite_foreign_key(name, opts) if name.is_a?(Array)
110:         column(name, Integer, opts)
111:       end

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

[Source]

     # File lib/sequel/database/schema_generator.rb, line 114
114:       def full_text_index(columns, opts = {})
115:         index(columns, opts.merge(:type => :full_text))
116:       end

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

[Source]

     # File lib/sequel/database/schema_generator.rb, line 119
119:       def has_column?(name)
120:         columns.any?{|c| c[:name] == name}
121:       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 129
129:       def index(columns, opts = {})
130:         indexes << {:columns => Array(columns)}.merge(opts)
131:       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 135
135:       def method_missing(type, name = nil, opts = {})
136:         name ? column(name, type, opts) : super
137:       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 151
151:       def primary_key(name, *args)
152:         return composite_primary_key(name, *args) if name.is_a?(Array)
153:         @primary_key = @db.serial_primary_key_options.merge({:name => name})
154:         
155:         if opts = args.pop
156:           opts = {:type => opts} unless opts.is_a?(Hash)
157:           if type = args.pop
158:             opts.merge!(:type => type)
159:           end
160:           @primary_key.merge!(opts)
161:         end
162:         @primary_key
163:       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 166
166:       def primary_key_name
167:         @primary_key[:name] if @primary_key
168:       end

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

[Source]

     # File lib/sequel/database/schema_generator.rb, line 171
171:       def spatial_index(columns, opts = {})
172:         index(columns, opts.merge(:type => :spatial))
173:       end

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

[Source]

     # File lib/sequel/database/schema_generator.rb, line 176
176:       def unique(columns, opts = {})
177:         constraints << {:type => :unique, :columns => Array(columns)}.merge(opts)
178:       end

[Validate]