Schema::CreateTableGenerator 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::CreateTableGenerator 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 “Schema Modification” guide.
Methods
Public Class
Public Instance
Constants
| GENERIC_TYPES | = | %w'String Integer Float Numeric BigDecimal Date DateTime Time File TrueClass FalseClass'.freeze |
Classes specifying generic types that |
Attributes
| columns | [R] |
Column hashes created by this generator |
| constraints | [R] |
Constraint hashes created by this generator |
| indexes | [R] |
Index hashes 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.
# File lib/sequel/database/schema_generator.rb 59 def self.add_type_method(*types) 60 types.each do |type| 61 case type 62 when Symbol, String 63 method = type 64 type = Object.const_get(type) 65 else 66 method = type.to_s 67 end 68 69 define_method(method){|name, opts=OPTS| column(name, type, opts)} 70 end 71 nil 72 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 34 def initialize(db, &block) 35 @db = db 36 @columns = [] 37 @indexes = [] 38 @constraints = [] 39 @primary_key = nil 40 instance_exec(&block) if block 41 end
Public Instance methods
Use custom Bignum method to use :Bignum instead of Bignum class, to work correctly in cases where Bignum is the same as Integer.
# File lib/sequel/database/schema_generator.rb 45 def Bignum(name, opts=OPTS) 46 column(name, :Bignum, opts) 47 end
# File lib/sequel/database/schema_generator.rb 51 def Fixnum(name, opts=OPTS) 52 column(name, Integer, opts) 53 end
Add an unnamed constraint, 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 79 def check(*args, &block) 80 constraint(nil, *args, &block) 81 end
Add a column with the given name, type, and opts:
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:
| :collate |
The collation to use for the column. For backwards compatibility, only symbols and string values are supported, and they are used verbatim. However, on PostgreSQL, symbols are literalized as regular identifiers, since unquoted collations are unlikely to be valid. | ||||||||
| :default |
The default value for the column. | ||||||||
| :deferrable |
For foreign key columns, this ensures referential integrity will work even if referencing table uses a foreign key value that does not yet exist on referenced table (but will exist before the transaction commits). Basically it adds DEFERRABLE INITIALLY DEFERRED on key creation. If you use :immediate as the value, uses DEFERRABLE INITIALLY IMMEDIATE. | ||||||||
| :generated_always_as |
Specify a GENERATED ALWAYS AS column expression, if generated columns are supported (PostgreSQL 12+, MariaDB 5.2.0+, and MySQL 5.7.6+). | ||||||||
| :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. | ||||||||
| :not_null |
Similar to setting
| ||||||||
| :null |
Mark the column as allowing NULL values (if true), or not allowing NULL values (if false). The default is to allow NULL values. | ||||||||
| :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 not be used if you want a single autoincrementing primary key column (use the
| ||||||||
| :primary_key_constraint_name |
Older option to name primary key constraint. | ||||||||
| :primary_key_deferrable |
Older option to set primary key constraint as deferrable. | ||||||||
| :type |
Overrides the type given as the argument. Generally not used by column itself, but can be passed as an option to other methods that call column. | ||||||||
| :unique |
Mark the column as unique, generally has the same effect as creating a unique index on the column. Can be a hash to provide options for the constraint:
| ||||||||
| :unique_constraint_name |
Older option to name unique constraint. | ||||||||
| :unique_deferrable |
Older option to set unique constraint as deferrable. |
PostgreSQL specific options:
| :identity |
Create an identity column. |
MySQL specific options:
| :generated_type |
Set the type of column when using :generated_always_as, should be :virtual or :stored to force a type. |
| :on_update_current_timestamp |
Use ON UPDATE CURRENT TIMESTAMP when defining the column, which will update the column value to CURRENT_TIMESTAMP on every UPDATE. |
Microsoft SQL Server specific options:
| :clustered |
When using :primary_key or :unique, marks the primary key or unique constraint as CLUSTERED (if true), or NONCLUSTERED (if false). |
# File lib/sequel/database/schema_generator.rb 172 def column(name, type, opts = OPTS) 173 columns << {:name => name, :type => type}.merge!(opts) 174 if index_opts = opts[:index] 175 index(name, index_opts.is_a?(Hash) ? index_opts : OPTS) 176 end 177 nil 178 end
Adds a named CHECK constraint (or unnamed if name is nil), with the given block or args. To provide options for the constraint, pass a hash as the first argument.
constraint(:blah, num: 1..5) # CONSTRAINT blah CHECK num >= 1 AND num <= 5 constraint({name: :blah, deferrable: true}, num: 1..5) # CONSTRAINT blah CHECK num >= 1 AND num <= 5 DEFERRABLE INITIALLY DEFERRED
If the first argument is a hash, the following options are supported:
Options:
| :name |
The name of the CHECK constraint |
| :deferrable |
Whether the CHECK constraint should be marked DEFERRABLE. |
PostgreSQL specific options:
| :no_inherit |
Set NO INHERIT on the constraint, so it will not propogate to child tables. |
| :not_enforced |
Whether the CHECK constraint should be marked NOT ENFORCED. |
| :not_valid |
Whether the CHECK constraint should be marked NOT VALID. |
# File lib/sequel/database/schema_generator.rb 200 def constraint(name, *args, &block) 201 opts = name.is_a?(Hash) ? name : {:name=>name} 202 constraints << opts.merge(:type=>:check, :check=>block || args) 203 nil 204 end
Add a foreign key in the table that references another table. 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) foreign_key(:artist_id, :artists, type: String) # artist_id varchar(255) REFERENCES artists(id)
Additional Options:
| :foreign_key_constraint_name |
The name to give the foreign key constraint |
PostgreSQL specific options:
| :not_enforced |
Whether the foreign key constraint should be marked NOT ENFORCED. |
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. This changes the method to accept constraint options instead of column options. You can provide the :name option to name the constraint.
PostgreSQL specific options:
| :not_enforced |
Whether the foreign key constraint should be marked NOT ENFORCED. |
| :period |
Use PERIOD to setup a constraint where the final column is a range or multirange column, and the range or multirange is covered by existing ranges in the referenced table (which can be in separate rows). |
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 236 def foreign_key(name, table=nil, opts = OPTS) 237 opts = case table 238 when Hash 239 table.merge(opts) 240 when NilClass 241 opts 242 else 243 opts.merge(:table=>table) 244 end 245 return composite_foreign_key(name, opts) if name.is_a?(Array) 246 column(name, Integer, opts) 247 end
Add a full text index on the given columns. See index for additional options.
PostgreSQL specific options:
| :index_type |
Can be set to :gist to use a GIST index instead of the default GIN index. |
| :language |
Set a language to use for the index (default: simple). |
# File lib/sequel/database/schema_generator.rb 256 def full_text_index(columns, opts = OPTS) 257 index(columns, opts.merge(:type => :full_text)) 258 end
True if the generator includes the creation of a column with the given name.
# File lib/sequel/database/schema_generator.rb 261 def has_column?(name) 262 columns.any?{|c| c[:name] == name} 263 end
Add an index on the given column(s) with the given options. Examples:
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) index [:artist_id, :name], name: :foo # CREATE INDEX foo ON table (artist_id, name)
General options:
| :include |
Include additional column values in the index, without actually indexing on those values (only supported by some databases). |
| :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, :full_text and :spatial values are handled specially). |
| :unique |
Make the index unique, so duplicate values are not allowed. |
| :where |
A filter expression, used to 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. |
| :if_not_exists |
Only create the index if an index of the same name doesn’t already exist. |
| :nulls_distinct |
Set whether separate NULLs should be considered distinct values in unique indexes. |
| :opclass |
Set an opclass to use for all columns (per-column opclasses require custom |
| :tablespace |
Specify tablespace for index. |
Microsoft SQL Server specific options:
| :key_index |
Sets the KEY INDEX to the given value. |
# File lib/sequel/database/schema_generator.rb 303 def index(columns, opts = OPTS) 304 indexes << {:columns => Array(columns)}.merge!(opts) 305 nil 306 end
Add a column with the given type, name, and opts. See column for available options.
# File lib/sequel/database/schema_generator.rb 310 def method_missing(type, name = nil, opts = OPTS) 311 name ? column(name, type, opts) : super 312 end
Adds an autoincrementing primary key column or a primary key constraint. To just 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.
If an array of column symbols is used, you can specify the :name option to name the constraint.
Options:
| :keep_order |
For non-composite primary keys, respects the existing order of columns, overriding the default behavior of making the primary key the first column. |
PostgreSQL specific options:
| :include |
Include additional columns in the underlying index, to allow for index-only scans in more cases (PostgreSQL 11+). |
| :without_overlaps |
Use WITHOUT OVERLAPS clause to specify an exclusion constraint on the final column (PostgreSQL 18+, composite primary keys only). |
Examples:
primary_key(:id) primary_key(:id, type: :Bignum, keep_order: true) primary_key([:street_number, :house_number], name: :some_constraint_name)
# File lib/sequel/database/schema_generator.rb 348 def primary_key(name, *args) 349 return composite_primary_key(name, *args) if name.is_a?(Array) 350 column = @db.serial_primary_key_options.merge({:name => name}) 351 352 if opts = args.pop 353 opts = {:type => opts} unless opts.is_a?(Hash) 354 if type = args.pop 355 opts = opts.merge(:type => type) 356 end 357 column.merge!(opts) 358 end 359 360 @primary_key = column 361 if column[:keep_order] 362 columns << column 363 else 364 columns.unshift(column) 365 end 366 nil 367 end
The name of the primary key for this generator, if it has a primary key.
# File lib/sequel/database/schema_generator.rb 370 def primary_key_name 371 @primary_key[:name] if @primary_key 372 end
This object responds to all methods.
# File lib/sequel/database/schema_generator.rb 315 def respond_to_missing?(meth, include_private) 316 true 317 end
Add a spatial index on the given columns. See index for additional options.
# File lib/sequel/database/schema_generator.rb 376 def spatial_index(columns, opts = OPTS) 377 index(columns, opts.merge(:type => :spatial)) 378 end
Add a unique constraint on the given columns.
unique(:name) # UNIQUE (name)
Supports the same :deferrable option as column. The :name option can be used to name the constraint.
PostgreSQL specific options:
| :include |
Include additional columns in the underlying index, to allow for index-only scans in more cases (PostgreSQL 11+). |
| :nulls_not_distinct |
Use NULLS NOT DISTINCT to setup a constraint where NULL entries are considered distinct (PostgreSQL 15+) |
| :without_overlaps |
Use WITHOUT OVERLAPS clause to specify an exclusion constraint on the final column (PostgreSQL 18+, composite unique only). |
# File lib/sequel/database/schema_generator.rb 395 def unique(columns, opts = OPTS) 396 constraints << {:type => :unique, :columns => Array(columns)}.merge!(opts) 397 nil 398 end