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.
For more information on Sequel‘s support for schema modification, see the "Migrations and Schema Modification" guide.
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 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 |
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 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.
# 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
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
# 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. If given a hash, use the hash as the options for the index. |
: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. |
:unique : | Mark the column as unique, generally has the same effect as creating a unique index on the column. |
# File lib/sequel/database/schema_generator.rb, line 103 103: def column(name, type, opts = {}) 104: columns << {:name => name, :type => type}.merge(opts) 105: if index_opts = opts[:index] 106: index(name, index_opts.is_a?(Hash) ? index_opts : {}) 107: end 108: 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
# File lib/sequel/database/schema_generator.rb, line 115 115: def constraint(name, *args, &block) 116: constraints << {:name => name, :type => :check, :check => block || args} 117: 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 387 387: def dump_columns 388: strings = [] 389: cols = columns.dup 390: cols.each do |x| 391: x.delete(:on_delete) if x[:on_delete] == :no_action 392: x.delete(:on_update) if x[:on_update] == :no_action 393: end 394: if pkn = primary_key_name 395: cols.delete_if{|x| x[:name] == pkn} 396: pk = @primary_key.dup 397: pkname = pk.delete(:name) 398: @db.serial_primary_key_options.each{|k,v| pk.delete(k) if v == pk[k]} 399: strings << "primary_key #{pkname.inspect}#{opts_inspect(pk)}" 400: end 401: cols.each do |c| 402: c = c.dup 403: name = c.delete(:name) 404: strings << if table = c.delete(:table) 405: c.delete(:type) if c[:type] == Integer || c[:type] == 'integer' 406: "foreign_key #{name.inspect}, #{table.inspect}#{opts_inspect(c)}" 407: else 408: type = c.delete(:type) 409: opts = opts_inspect(c) 410: if type.is_a?(Class) 411: "#{type.name} #{name.inspect}#{opts}" 412: else 413: "column #{name.inspect}, #{type.inspect}#{opts}" 414: end 415: end 416: end 417: strings.join("\n") 418: 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 422 422: def dump_constraints 423: cs = constraints.map do |c| 424: c = c.dup 425: type = c.delete(:type) 426: case type 427: when :check 428: raise(Error, "can't dump check/constraint specified with Proc") if c[:check].is_a?(Proc) 429: name = c.delete(:name) 430: if !name and c[:check].length == 1 and c[:check].first.is_a?(Hash) 431: "check #{c[:check].first.inspect[1...-1]}" 432: else 433: "#{name ? "constraint #{name.inspect}," : 'check'} #{c[:check].map{|x| x.inspect}.join(', ')}" 434: end 435: when :foreign_key 436: c.delete(:on_delete) if c[:on_delete] == :no_action 437: c.delete(:on_update) if c[:on_update] == :no_action 438: c.delete(:deferrable) unless c[:deferrable] 439: cols = c.delete(:columns) 440: table = c.delete(:table) 441: "#{type} #{cols.inspect}, #{table.inspect}#{opts_inspect(c)}" 442: else 443: cols = c.delete(:columns) 444: "#{type} #{cols.inspect}#{opts_inspect(c)}" 445: end 446: end 447: cs.join("\n") 448: 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 457 457: def dump_indexes(options={}) 458: is = indexes.map do |c| 459: c = c.dup 460: cols = c.delete(:columns) 461: if table = options[:add_index] || options[:drop_index] 462: "#{options[:drop_index] ? 'drop' : 'add'}_index #{table.inspect}, #{cols.inspect}#{', :ignore_errors=>true' if options[:ignore_errors]}#{opts_inspect(c)}" 463: else 464: "index #{cols.inspect}#{opts_inspect(c)}" 465: end 466: end 467: is = is.reverse if options[:drop_index] 468: is.join("\n") 469: 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
# File lib/sequel/database/schema_generator.rb, line 132 132: def foreign_key(name, table=nil, opts = {}) 133: opts = case table 134: when Hash 135: table.merge(opts) 136: when Symbol 137: opts.merge(:table=>table) 138: when NilClass 139: opts 140: else 141: raise(Error, "The second argument to foreign_key should be a Hash, Symbol, or nil") 142: end 143: return composite_foreign_key(name, opts) if name.is_a?(Array) 144: column(name, Integer, opts) 145: end
Add a full text index on the given columns to the DDL.
PostgreSQL specific options:
:language : | Set a language to use for the index (default: simple). |
Microsoft SQL Server specific options:
:key_index : | The KEY INDEX to use for the full text index. |
# File lib/sequel/database/schema_generator.rb, line 154 154: def full_text_index(columns, opts = {}) 155: index(columns, opts.merge(:type => :full_text)) 156: end
Add an index on the given column(s) with the given options to the DDL. General options:
:name : | The name to use for the index. If not given, a default name based on the table and columns is used. |
: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) |
PostgreSQL specific options:
:concurrently : | Create the index concurrently, so it doesn‘t block operations on the table while the index is being built. |
:op_class : | Use a specific operator class in the index. |
Microsoft SQL Server specific options:
:include : | Include additional column values in the index, without actually indexing on those values. |
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)
# File lib/sequel/database/schema_generator.rb, line 189 189: def index(columns, opts = {}) 190: indexes << {:columns => Array(columns)}.merge(opts) 191: 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])
# File lib/sequel/database/schema_generator.rb, line 212 212: def primary_key(name, *args) 213: return composite_primary_key(name, *args) if name.is_a?(Array) 214: @primary_key = @db.serial_primary_key_options.merge({:name => name}) 215: 216: if opts = args.pop 217: opts = {:type => opts} unless opts.is_a?(Hash) 218: if type = args.pop 219: opts.merge!(:type => type) 220: end 221: @primary_key.merge!(opts) 222: end 223: @primary_key 224: end
The name of the primary key for this generator, if it has a primary key.
# File lib/sequel/database/schema_generator.rb, line 227 227: def primary_key_name 228: @primary_key[:name] if @primary_key 229: end
Add a unique constraint on the given columns to the DDL.
unique(:name) # UNIQUE (name)
# File lib/sequel/database/schema_generator.rb, line 239 239: def unique(columns, opts = {}) 240: constraints << {:type => :unique, :columns => Array(columns)}.merge(opts) 241: end