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. |
: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 |
The name to give the primary key constraint |
:primary_key_deferrable |
Similar to :deferrable, but for the primary key constraint if :primary_key is used. |
: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. |
:unique_constraint_name |
The name to give the unique key constraint |
:unique_deferrable |
Similar to :deferrable, but for the unique constraint if :unique is used. |
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 157 def column(name, type, opts = OPTS) 158 columns << {:name => name, :type => type}.merge!(opts) 159 if index_opts = opts[:index] 160 index(name, index_opts.is_a?(Hash) ? index_opts : OPTS) 161 end 162 nil 163 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:
:not_valid |
Whether the CHECK constraint should be marked NOT VALID. |
# File lib/sequel/database/schema_generator.rb 182 def constraint(name, *args, &block) 183 opts = name.is_a?(Hash) ? name : {:name=>name} 184 constraints << opts.merge(:type=>:check, :check=>block || args) 185 nil 186 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 |
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 206 def foreign_key(name, table=nil, opts = OPTS) 207 opts = case table 208 when Hash 209 table.merge(opts) 210 when NilClass 211 opts 212 else 213 opts.merge(:table=>table) 214 end 215 return composite_foreign_key(name, opts) if name.is_a?(Array) 216 column(name, Integer, opts) 217 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 226 def full_text_index(columns, opts = OPTS) 227 index(columns, opts.merge(:type => :full_text)) 228 end
True if the generator includes the creation of a column with the given name.
# File lib/sequel/database/schema_generator.rb 231 def has_column?(name) 232 columns.any?{|c| c[:name] == name} 233 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 273 def index(columns, opts = OPTS) 274 indexes << {:columns => Array(columns)}.merge!(opts) 275 nil 276 end
Add a column with the given type, name, and opts. See column
for available options.
# File lib/sequel/database/schema_generator.rb 280 def method_missing(type, name = nil, opts = OPTS) 281 name ? column(name, type, opts) : super 282 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. |
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 311 def primary_key(name, *args) 312 return composite_primary_key(name, *args) if name.is_a?(Array) 313 column = @db.serial_primary_key_options.merge({:name => name}) 314 315 if opts = args.pop 316 opts = {:type => opts} unless opts.is_a?(Hash) 317 if type = args.pop 318 opts = opts.merge(:type => type) 319 end 320 column.merge!(opts) 321 end 322 323 @primary_key = column 324 if column[:keep_order] 325 columns << column 326 else 327 columns.unshift(column) 328 end 329 nil 330 end
The name of the primary key for this generator, if it has a primary key.
# File lib/sequel/database/schema_generator.rb 333 def primary_key_name 334 @primary_key[:name] if @primary_key 335 end
This object responds to all methods.
# File lib/sequel/database/schema_generator.rb 285 def respond_to_missing?(meth, include_private) 286 true 287 end
Add a spatial index on the given columns. See index
for additional options.
# File lib/sequel/database/schema_generator.rb 339 def spatial_index(columns, opts = OPTS) 340 index(columns, opts.merge(:type => :spatial)) 341 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.
# File lib/sequel/database/schema_generator.rb 349 def unique(columns, opts = OPTS) 350 constraints << {:type => :unique, :columns => Array(columns)}.merge!(opts) 351 nil 352 end