Sequel

Top level module for Sequel

There are some module methods that are added via metaprogramming, one for each supported adapter. For example:

DB = Sequel.sqlite # Memory database
DB = Sequel.sqlite('blog.db')
DB = Sequel.postgres('database_name',
       user:'user', 
       password: 'password',
       host: 'host'
       port: 5432, 
       max_connections: 10)

If a block is given to these methods, it is passed the opened Database object, which is closed (disconnected) when the block exits, just like a block passed to Sequel.connect. For example:

Sequel.sqlite('blog.db'){|db| puts db[:users].count}

For a more expanded introduction, see the README. For a quicker introduction, see the cheat sheet.

Methods

Included modules

SQL::Constants

Constants

ADAPTER_MAP	=	{}	Hash of adapters that have been used. The key is the adapter scheme symbol, and the value is the `Database` subclass.
AdapterNotFound	=	Class.new(Error)	`Error` raised when the adapter requested doesn’t exist or can’t be loaded.
AdvisoryLockError	=	Class.new(Error)	`Error` raised when there is a failed attempt to acquire an advisory lock.
CheckConstraintViolation	=	Class.new(ConstraintViolation)	`Error` raised when `Sequel` determines a database check constraint has been violated.
ConstraintViolation	=	Class.new(DatabaseError)	Generic error raised when `Sequel` determines a database constraint has been violated.
DATABASES	=	[]	Array of all databases to which `Sequel` has connected. If you are developing an application that can connect to an arbitrary number of databases, delete the database objects from this (or use the :keep_reference `Database` option or a block when connecting) or they will not get garbage collected.
DEFAULT_INFLECTIONS_PROC	=	proc do plural(/$/, 's') plural(/s$/i, 's') plural(/(alias\|(?:stat\|octop\|vir\|b)us)$/i, '\1es') plural(/(buffal\|tomat)o$/i, '\1oes') plural(/([ti])um$/i, '\1a') plural(/sis$/i, 'ses') plural(/(?:([^f])fe\|([lr])f)$/i, '\1\2ves') plural(/(hive)$/i, '\1s') plural(/([^aeiouy]\|qu)y$/i, '\1ies') plural(/(x\|ch\|ss\|sh)$/i, '\1es') plural(/(matr\|vert\|ind)ix\|ex$/i, '\1ices') plural(/([m\|l])ouse$/i, '\1ice') singular(/s$/i, '') singular(/([ti])a$/i, '\1um') singular(/(analy\|ba\|cri\|diagno\|parenthe\|progno\|synop\|the)ses$/i, '\1sis') singular(/([^f])ves$/i, '\1fe') singular(/([h\|t]ive)s$/i, '\1') singular(/([lr])ves$/i, '\1f') singular(/([^aeiouy]\|qu)ies$/i, '\1y') singular(/(m)ovies$/i, '\1ovie') singular(/(x\|ch\|ss\|sh)es$/i, '\1') singular(/([m\|l])ice$/i, '\1ouse') singular(/buses$/i, 'bus') singular(/oes$/i, 'o') singular(/shoes$/i, 'shoe') singular(/(alias\|(?:stat\|octop\|vir\|b)us)es$/i, '\1') singular(/(vert\|ind)ices$/i, '\1ex') singular(/matrices$/i, 'matrix') irregular('person', 'people') irregular('man', 'men') irregular('child', 'children') irregular('sex', 'sexes') irregular('move', 'moves') irregular('quiz', 'quizzes') irregular('testis', 'testes') uncountable(%w(equipment information rice money species series fish sheep news)) end	Proc that is instance_execed to create the default inflections for both the model inflector and the inflector extension.
DatabaseConnectionError	=	Class.new(DatabaseError)	`Error` raised when the `Sequel` is unable to connect to the database with the connection parameters it was given.
DatabaseDisconnectError	=	Class.new(DatabaseError)	`Error` raised by adapters when they determine that the connection to the database has been lost. Instructs the connection pool code to remove that connection from the pool so that other connections can be acquired automatically.
DatabaseError	=	Class.new(Error)	Generic error raised by the database adapters, indicating a problem originating from the database server. Usually raised because incorrect `SQL` syntax is used.
DatabaseLockTimeout	=	Class.new(DatabaseError)	`Error` raised when `Sequel` determines the database could not acquire a necessary lock before timing out. Use of `Dataset#nowait` can often cause this exception when retrieving rows.
ForeignKeyConstraintViolation	=	Class.new(ConstraintViolation)	`Error` raised when `Sequel` determines a database foreign key constraint has been violated.
InvalidOperation	=	Class.new(Error)	`Error` raised on an invalid operation, such as trying to update or delete a joined or grouped dataset when the database does not support that.
InvalidValue	=	Class.new(Error)	`Error` raised when attempting an invalid type conversion.
MAJOR	=	5	The major version of `Sequel`. Only bumped for major changes.
MINOR	=	98	The minor version of `Sequel`. Bumped for every non-patch level release, generally around once a month.
NoExistingObject	=	Class.new(Error)	Exception class raised when `require_modification` is set and an UPDATE or DELETE statement to modify the dataset doesn’t modify a single row.
NotNullConstraintViolation	=	Class.new(ConstraintViolation)	`Error` raised when `Sequel` determines a database NOT NULL constraint has been violated.
OPTS	=	{}.freeze	Frozen hash used as the default options hash for most options.
PoolTimeout	=	Class.new(Error)	`Error` raised when the connection pool cannot acquire a database connection before the timeout.
Rollback	=	Class.new(Error)	`Error` that you should raise to signal a rollback of the current transaction. The transaction block will catch this exception, rollback the current transaction, and won’t reraise it (unless a reraise is requested).
SHARED_ADAPTER_MAP	=	{}	Hash of shared adapters that have been registered. The key is the adapter scheme symbol, and the value is the `Sequel` module containing the shared adapter.
SPLIT_SYMBOL_CACHE	=	{}
SerializationFailure	=	Class.new(DatabaseError)	`Error` raised when `Sequel` determines a serialization failure/deadlock in the database.
TINY	=	0	The tiny version of `Sequel`. Usually 0, only bumped for bugfix releases that fix regressions from previous versions.
Timezones	=	SequelMethods	Backwards compatible alias
UndefinedAssociation	=	Class.new(Error)	Raised when an undefined association is used when eager loading.
UniqueConstraintViolation	=	Class.new(ConstraintViolation)	`Error` raised when `Sequel` determines a database unique constraint has been violated.
VERSION	=	[MAJOR, MINOR, TINY].join('.').freeze	The version of `Sequel` you are using, as a string (e.g. “2.11.0”)
VERSION_NUMBER	=	MAJOR10000 + MINOR10 + TINY	The version of `Sequel` you are using, as a number (2.11.0 -> 20110)
VIRTUAL_ROW	=	new

Public Class methods

inflections()

Yield the Inflections module if a block is given, and return the Inflections module.

[show source]

  # File lib/sequel/model/inflections.rb
6 def self.inflections
7   yield Inflections if defined?(yield)
8   Inflections
9 end

migration(&block)

The preferred method for writing Sequel migrations, using a DSL:

Sequel.migration do
  up do
    create_table(:artists) do
      primary_key :id
      String :name
    end
  end

  down do
    drop_table(:artists)
  end
end

Designed to be used with the Migrator class, part of the migration extension.

[show source]

    # File lib/sequel/extensions/migration.rb
312 def self.migration(&block)
313   MigrationDSL.create(&block)
314 end

version()

The version of Sequel you are using, as a string (e.g. “2.11.0”)

[show source]

   # File lib/sequel/version.rb
22 def self.version
23   VERSION
24 end

module Sequel

Methods

Public Class

Included modules

Classes and Modules

Constants

Public Class methods