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Sequel::Schema::CreateTableGenerator

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 "Migrations and Schema Modification" guide.

Constants

GENERIC_TYPES

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) click to toggle source

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
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) click to toggle source

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
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) click to toggle source

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
def check(*args, &block)
  constraint(nil, *args, &block)
end
column(name, type, opts = {}) click to toggle source

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.

: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.

# File lib/sequel/database/schema_generator.rb, line 105
def column(name, type, opts = {})
  columns << {:name => name, :type => type}.merge(opts)
  if index_opts = opts[:index]
    index(name, index_opts.is_a?(Hash) ? index_opts : {})
  end
end
constraint(name, *args, &block) click to toggle source

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 117
def constraint(name, *args, &block)
  constraints << {:name => name, :type => :check, :check => block || args}
end
foreign_key(name, table=nil, opts = {}) click to toggle source

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)
foreign_key(:artist_id, :artists, :type=>String) # artist_id varchar(255) 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 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 = {}) click to toggle source

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 157
def full_text_index(columns, opts = {})
  index(columns, opts.merge(:type => :full_text))
end
has_column?(name) click to toggle source

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

# File lib/sequel/database/schema_generator.rb, line 162
def has_column?(name)
  columns.any?{|c| c[:name] == name}
end
index(columns, opts = {}) click to toggle source

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 192
def index(columns, opts = {})
  indexes << {:columns => Array(columns)}.merge(opts)
end
method_missing(type, name = nil, opts = {}) click to toggle source

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

# File lib/sequel/database/schema_generator.rb, line 198
def method_missing(type, name = nil, opts = {})
  name ? column(name, type, opts) : super
end
primary_key(name, *args) click to toggle source

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 215
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() click to toggle source

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

# File lib/sequel/database/schema_generator.rb, line 230
def primary_key_name
  @primary_key[:name] if @primary_key
end
spatial_index(columns, opts = {}) click to toggle source

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

# File lib/sequel/database/schema_generator.rb, line 235
def spatial_index(columns, opts = {})
  index(columns, opts.merge(:type => :spatial))
end
unique(columns, opts = {}) click to toggle source

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

unique(:name) # UNIQUE (name)
# File lib/sequel/database/schema_generator.rb, line 242
def unique(columns, opts = {})
  constraints << {:type => :unique, :columns => Array(columns)}.merge(opts)
end

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