| 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.
| 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 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.
# 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
# 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
# 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:
# 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.
# 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 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 131
131: def index(columns, opts = {})
132: indexes << {:columns => Array(columns)}.merge(opts)
133: 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 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.
# 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 unique constraint on the given columns to the DDL.
# 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