| 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.
| 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. |
| 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 |
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 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.
# 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
Add a unnamed constraint to the DDL, specified by the given block or args.
# 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:
# 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.
# 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
# File lib/sequel/extensions/schema_dumper.rb, line 169
169: def dump_columns
170: strings = []
171: cols = columns.dup
172: if pkn = primary_key_name
173: cols.delete_if{|x| x[:name] == pkn}
174: pk = @primary_key.dup
175: pkname = pk.delete(:name)
176: @db.serial_primary_key_options.each{|k,v| pk.delete(k) if v == pk[k]}
177: strings << "primary_key #{pkname.inspect}#{opts_inspect(pk)}"
178: end
179: cols.each do |c|
180: c = c.dup
181: name = c.delete(:name)
182: type = c.delete(:type)
183: opts = opts_inspect(c)
184: strings << if type.is_a?(Class)
185: "#{type.name} #{name.inspect}#{opts}"
186: else
187: "column #{name.inspect}, #{type.inspect}#{opts}"
188: end
189: end
190: strings.join("\n")
191: end
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 195
195: def dump_constraints
196: constraints.map do |c|
197: c = c.dup
198: type = c.delete(:type)
199: case type
200: when :check
201: raise(Error, "can't dump check/constraint specified with Proc") if c[:check].is_a?(Proc)
202: name = c.delete(:name)
203: if !name and c[:check].length == 1 and c[:check].first.is_a?(Hash)
204: "check #{c[:check].first.inspect[1...-1]}"
205: else
206: "#{name ? "constraint #{name.inspect}," : 'check'} #{c[:check].map{|x| x.inspect}.join(', ')}"
207: end
208: else
209: cols = c.delete(:columns)
210: "#{type} #{cols.inspect}#{opts_inspect(c)}"
211: end
212: end.join("\n")
213: end
Dump this generator‘s indexes to a string that could be evaled inside another instance to represent the same indexes. Options:
# File lib/sequel/extensions/schema_dumper.rb, line 221
221: def dump_indexes(options={})
222: indexes.map do |c|
223: c = c.dup
224: cols = c.delete(:columns)
225: if table = options[:add_index] || options[:drop_index]
226: "#{options[:drop_index] ? 'drop' : 'add'}_index #{table.inspect}, #{cols.inspect}#{opts_inspect(c)}"
227: else
228: "index #{cols.inspect}#{opts_inspect(c)}"
229: end
230: end.join("\n")
231: end
Add a foreign key in the table that references another table to the DDL. See column for available options.
# 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 an index on the given column(s) with the given options to the DDL. The available options are:
# File lib/sequel/database/schema_generator.rb, line 129
129: def index(columns, opts = {})
130: indexes << {:columns => Array(columns)}.merge(opts)
131: 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)
# 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.
# 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 unique constraint on the given columns to the DDL.
# 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