Sequel::Schema::Generator

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.

Methods

Public Instance

check
column
columns
constraint
constraints
foreign_key
full_text_index
has_column?
index
indexes
method_missing
primary_key
primary_key_name
spatial_index
unique

Constants

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.

Attributes

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

Public Class methods

add_type_method (*types)

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.

[show source]

# File lib/sequel/database/schema_generator.rb, line 47
def self.add_type_method(*types)
  types.each do |type|
    class_eval("def #{type}(name, opts={}); column(name, #{type}, opts); end", __FILE__, __LINE__)
  end
end

new (db, &block)

Set the database in which to create the table, and evaluate the block in the context of this object.

[show source]

# File lib/sequel/database/schema_generator.rb, line 33
def initialize(db, &block)
  @db = db
  @columns = []
  @indexes = []
  @constraints = []
  @primary_key = nil
  instance_eval(&block) if block
  @columns.unshift(@primary_key) if @primary_key && !has_column?(primary_key_name)
end

Public Instance methods

check (*args, &block)

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

[show source]

# File lib/sequel/database/schema_generator.rb, line 58
def check(*args, &block)
  constraint(nil, *args, &block)
end

column (name, type, opts = {})

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.
: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.
:size	The size of the column, generally used with string columns to specify the maximum number of characters the column will hold. An array of two integers can be provided to set the size and the precision, respectively, of decimal columns.
:unique	Mark the column as unique, generally has the same effect as creating a unique index on the column.
:unsigned	Make the column type unsigned, only useful for integer columns.

[show source]

# File lib/sequel/database/schema_generator.rb, line 108
def column(name, type, opts = {})
  columns << {:name => name, :type => type}.merge(opts)
  index(name) if opts[:index]
end

constraint (name, *args, &block)

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

[show source]

# File lib/sequel/database/schema_generator.rb, line 118
def constraint(name, *args, &block)
  constraints << {:name => name, :type => :check, :check => block || args}
end

foreign_key (name, table=nil, opts = {})

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

[show source]

# File lib/sequel/database/schema_generator.rb, line 135
def foreign_key(name, table=nil, opts = {})
  opts = case table
  when Hash
    table.merge(opts)
  when Symbol
    opts.merge(:table=>table)
  when NilClass
    opts
  else
    raise(Error, "The second argument to foreign_key should be a Hash, Symbol, or nil")
  end
  return composite_foreign_key(name, opts) if name.is_a?(Array)
  column(name, Integer, opts)
end

full_text_index (columns, opts = {})

Add a full text index on the given columns to the DDL.

[show source]

# File lib/sequel/database/schema_generator.rb, line 151
def full_text_index(columns, opts = {})
  index(columns, opts.merge(:type => :full_text))
end

has_column? (name)

True if the DDL includes the creation of a column with the given name.

[show source]

# File lib/sequel/database/schema_generator.rb, line 156
def has_column?(name)
  columns.any?{|c| c[:name] == name}
end

index (columns, opts = {})

Add an index on the given column(s) with the given options to the DDL. The available options are:

: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)

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)

[show source]

# File lib/sequel/database/schema_generator.rb, line 172
def index(columns, opts = {})
  indexes << {:columns => Array(columns)}.merge(opts)
end

method_missing (type, name = nil, opts = {})

Add a column with the given type, name, and opts to the DDL. See column for available options.

[show source]

# File lib/sequel/database/schema_generator.rb, line 178
def method_missing(type, name = nil, opts = {})
  name ? column(name, type, opts) : super
end

primary_key (name, *args)

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])

[show source]

# File lib/sequel/database/schema_generator.rb, line 195
def primary_key(name, *args)
  return composite_primary_key(name, *args) if name.is_a?(Array)
  @primary_key = @db.serial_primary_key_options.merge({:name => name})
  
  if opts = args.pop
    opts = {:type => opts} unless opts.is_a?(Hash)
    if type = args.pop
      opts.merge!(:type => type)
    end
    @primary_key.merge!(opts)
  end
  @primary_key
end

primary_key_name ()

The name of the primary key for this generator, if it has a primary key.

[show source]

# File lib/sequel/database/schema_generator.rb, line 210
def primary_key_name
  @primary_key[:name] if @primary_key
end

spatial_index (columns, opts = {})

Add a spatial index on the given columns to the DDL.

[show source]

# File lib/sequel/database/schema_generator.rb, line 215
def spatial_index(columns, opts = {})
  index(columns, opts.merge(:type => :spatial))
end

unique (columns, opts = {})

Add a unique constraint on the given columns to the DDL.

unique(:name) # UNIQUE (name)

[show source]

# File lib/sequel/database/schema_generator.rb, line 222
def unique(columns, opts = {})
  constraints << {:type => :unique, :columns => Array(columns)}.merge(opts)
end

class Sequel::Schema::Generator

Methods

Public Class

Public Instance

Constants

Attributes

Public Class methods

Public Instance methods