module Sequel

  1. lib/sequel/ast_transformer.rb
  2. lib/sequel/connection_pool.rb
  3. lib/sequel/connection_pool/sharded_single.rb
  4. lib/sequel/connection_pool/sharded_threaded.rb
  5. lib/sequel/connection_pool/single.rb
  6. lib/sequel/connection_pool/threaded.rb
  7. lib/sequel/core.rb
  8. lib/sequel/database.rb
  9. lib/sequel/database/connecting.rb
  10. lib/sequel/database/dataset.rb
  11. lib/sequel/database/dataset_defaults.rb
  12. lib/sequel/database/features.rb
  13. lib/sequel/database/logging.rb
  14. lib/sequel/database/misc.rb
  15. lib/sequel/database/query.rb
  16. lib/sequel/database/schema_generator.rb
  17. lib/sequel/database/schema_methods.rb
  18. lib/sequel/database/transactions.rb
  19. lib/sequel/dataset.rb
  20. lib/sequel/dataset/actions.rb
  21. lib/sequel/dataset/dataset_module.rb
  22. lib/sequel/dataset/features.rb
  23. lib/sequel/dataset/graph.rb
  24. lib/sequel/dataset/misc.rb
  25. lib/sequel/dataset/mutation.rb
  26. lib/sequel/dataset/placeholder_literalizer.rb
  27. lib/sequel/dataset/prepared_statements.rb
  28. lib/sequel/dataset/query.rb
  29. lib/sequel/dataset/sql.rb
  30. lib/sequel/deprecated.rb
  31. lib/sequel/exceptions.rb
  32. lib/sequel/extensions/migration.rb
  33. lib/sequel/model.rb
  34. lib/sequel/model/associations.rb
  35. lib/sequel/model/base.rb
  36. lib/sequel/model/dataset_module.rb
  37. lib/sequel/model/default_inflections.rb
  38. lib/sequel/model/errors.rb
  39. lib/sequel/model/exceptions.rb
  40. lib/sequel/model/inflections.rb
  41. lib/sequel/model/plugins.rb
  42. lib/sequel/no_core_ext.rb
  43. lib/sequel/sql.rb
  44. lib/sequel/timezones.rb
  45. lib/sequel/version.rb
  46. show all

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, 

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 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.



Hash of adapters that have been used. The key is the adapter scheme symbol, and the value is the Database subclass.

AdapterNotFound =  

Error raised when the adapter requested doesn't exist or can't be loaded.

BeforeHookFailed = HookFailed  

Exception class raised when raise_on_save_failure is set and a before hook returns false or an around hook doesn't call super or yield.

COLUMN_REF_RE1 = /\A((?:(?!__).)+)__((?:(?!___).)+)___(.+)\z/.freeze  
COLUMN_REF_RE2 = /\A((?:(?!___).)+)___(.+)\z/.freeze  
COLUMN_REF_RE3 = /\A((?:(?!__).)+)__(.+)\z/.freeze  
CheckConstraintViolation =  

Error raised when Sequel determines a database check constraint has been violated.

ConstraintViolation =  

Generic error raised when Sequel determines a database constraint has been violated.


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 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 evaled to create the default inflections for both the model inflector and the inflector extension.

DatabaseConnectionError =  

Error raised when the Sequel is unable to connect to the database with the connection parameters it was given.

DatabaseDisconnectError =  

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 =  

Generic error raised by the database adapters, indicating a problem originating from the database server. Usually raised because incorrect SQL syntax is used.

ForeignKeyConstraintViolation =  

Error raised when Sequel determines a database foreign key constraint has been violated.

InvalidOperation =  

Error raised on an invalid operation, such as trying to update or delete a joined or grouped dataset.

InvalidValue =  

Error raised when attempting an invalid type conversion.

MAJOR = 4  

The major version of Sequel. Only bumped for major changes.

MINOR = 49  

The minor version of Sequel. Bumped for every non-patch level release, generally around once a month.

MassAssignmentRestriction =  

Raised when a mass assignment method is called in strict mode with either a restricted column or a column without a setter method.

NoExistingObject =  

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 =  

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 =  

Error raised when the connection pool cannot acquire a database connection before the timeout.

Rollback =  

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).


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.

SerializationFailure =  

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.

UnbindDuplicate =  
UndefinedAssociation =  

Raised when an undefined association is used when eager loading.

UniqueConstraintViolation =  

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”)



convert_two_digit_years [RW]

Sequel converts two digit years in Dates and DateTimes by default, so 01/02/03 is interpreted at January 2nd, 2003, and 12/13/99 is interpreted as December 13, 1999. You can override this to treat those dates as January 2nd, 0003 and December 13, 0099, respectively, by:

Sequel.convert_two_digit_years = false
datetime_class [RW]

Sequel can use either Time or DateTime for times returned from the database. It defaults to Time. To change it to DateTime:

Sequel.datetime_class = DateTime

For ruby versions less than 1.9.2, Time has a limited range (1901 to 2038), so if you use datetimes out of that range, you need to switch to DateTime. Also, before 1.9.2, Time can only handle local and UTC times, not other timezones. Note that Time and DateTime objects have a different API, and in cases where they implement the same methods, they often implement them differently (e.g. + using seconds on Time and days on DateTime).

single_threaded [RW]

Set whether sequel is being used in single threaded mode. by default, Sequel uses a thread-safe connection pool, which isn't as fast as the single threaded connection pool, and also has some additional thread safety checks. If your program will only have one thread, and speed is a priority, you should set this to true:

Sequel.single_threaded = true

Public Class methods

cache_anonymous_models ()

Delegate to Sequel::Model, only for backwards compatibility.

[show source]
# File lib/sequel/model.rb, line 6
def self.cache_anonymous_models
  Sequel::Deprecation.deprecate("Sequel.cache_anonymous_models", "Use Sequel::Model.cache_anonymous_models")
cache_anonymous_models= (v)

Delegate to Sequel::Model, only for backwards compatibility.

[show source]
# File lib/sequel/model.rb, line 12
def self.cache_anonymous_models=(v)
  Sequel::Deprecation.deprecate("Sequel.cache_anonymous_models=", "Use Sequel::Model.cache_anonymous_models=")
  Model.cache_anonymous_models = v
condition_specifier? (obj)

Returns true if the passed object could be a specifier of conditions, false otherwise. Currently, Sequel considers hashes and arrays of two element arrays as condition specifiers.

Sequel.condition_specifier?({}) # => true
Sequel.condition_specifier?([[1, 2]]) # => true
Sequel.condition_specifier?([]) # => false
Sequel.condition_specifier?([1]) # => false
Sequel.condition_specifier?(1) # => false
[show source]
# File lib/sequel/core.rb, line 71
def self.condition_specifier?(obj)
  case obj
  when Hash
  when Array
    !obj.empty? && !obj.is_a?(SQL::ValueList) && obj.all?{|i| i.is_a?(Array) && (i.length == 2)}
connect (*args, &block)

Creates a new database object based on the supplied connection string and optional arguments. The specified scheme determines the database class used, and the rest of the string specifies the connection options. For example:

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

You can also pass a single options hash:

DB = Sequel.connect(:adapter=>'sqlite', :database=>'./blog.db')

If a block is given, it is passed the opened Database object, which is closed when the block exits. For example:

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

If a block is not given, a reference to this database will be held in Sequel::DATABASES until it is removed manually. This is by design, and used by Sequel::Model to pick the default database. It is recommended to pass a block if you do not want the resulting Database object to remain in memory until the process terminates.

For details, see the “Connecting to a Database” guide. To set up a master/slave or sharded database connection, see the “Master/Slave Databases and Sharding” guide.

[show source]
# File lib/sequel/core.rb, line 114
def self.connect(*args, &block)
  Database.connect(*args, &block)
convert_exception_class (exception, klass)

Convert the exception to the given class. The given class should be Sequel::Error or a subclass. Returns an instance of klass with the message and backtrace of exception.

[show source]
# File lib/sequel/core.rb, line 127
def self.convert_exception_class(exception, klass)
  return exception if exception.is_a?(klass)
  e ="#{exception.class}: #{exception.message}")
  e.wrapped_exception = exception
core_extensions? ()

Assume the core extensions are not loaded by default, if the core_extensions extension is loaded, this will be overridden.

[show source]
# File lib/sequel/core.rb, line 120
def self.core_extensions?
extension (*extensions)

Load all Sequel extensions given. Extensions are just files that exist under sequel/extensions in the load path, and are just required. Generally, extensions modify the behavior of Database and/or Dataset, but Sequel ships with some extensions that modify other classes that exist for backwards compatibility. In some cases, requiring an extension modifies classes directly, and in others, it just loads a module that you can extend other classes with. Consult the documentation for each extension you plan on using for usage.

Sequel.extension(:core_extensions, :named_timezones)
[show source]
# File lib/sequel/core.rb, line 145
def self.extension(*extensions)
  extensions.each{|e| Kernel.require "sequel/extensions/#{e}"}
identifier_input_method= (value)

Set the method to call on identifiers going into the database. This affects the literalization of identifiers by calling this method on them before they are input. Sequel upcases identifiers in all SQL strings for most databases, so to turn that off:

Sequel.identifier_input_method = nil

to downcase instead:

Sequel.identifier_input_method = :downcase

Other String instance methods work as well.

[show source]
# File lib/sequel/core.rb, line 160
def self.identifier_input_method=(value)
  # SEQUEL5: Remove
  Database.identifier_input_method = value
identifier_output_method= (value)

Set the method to call on identifiers coming out of the database. This affects the literalization of identifiers by calling this method on them when they are retrieved from the database. Sequel downcases identifiers retrieved for most databases, so to turn that off:

Sequel.identifier_output_method = nil

to upcase instead:

Sequel.identifier_output_method = :upcase

Other String instance methods work as well.

[show source]
# File lib/sequel/core.rb, line 177
def self.identifier_output_method=(value)
  # SEQUEL5: Remove
  Database.identifier_output_method = value
inflections ()

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

[show source]
# File lib/sequel/model/inflections.rb, line 5
def self.inflections
  yield Inflections if block_given?
json_parser_error_class ()

The exception classed raised if there is an error parsing JSON. This can be overridden to use an alternative json implementation.

[show source]
# File lib/sequel/core.rb, line 184
def self.json_parser_error_class
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

  down do

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

[show source]
# File lib/sequel/extensions/migration.rb, line 288
def self.migration(&block)
object_to_json (obj, *args, &block)

Convert given object to json and return the result. This can be overridden to use an alternative json implementation.

[show source]
# File lib/sequel/core.rb, line 190
def self.object_to_json(obj, *args, &block)
  obj.to_json(*args, &block)
parse_json (json)

Parse the string as JSON and return the result. This can be overridden to use an alternative json implementation.

[show source]
# File lib/sequel/core.rb, line 196
def self.parse_json(json)
  JSON.parse(json, :create_additions=>false)
quote_identifiers= (value)

Set whether to quote identifiers for all databases by default. By default, Sequel quotes identifiers in all SQL strings, so to turn that off:

Sequel.quote_identifiers = false
[show source]
# File lib/sequel/core.rb, line 204
def self.quote_identifiers=(value)
  # SEQUEL5: Remove
  Database.quote_identifiers = value
recursive_map (array, converter)

Convert each item in the array to the correct type, handling multi-dimensional arrays. For each element in the array or subarrays, call the converter, unless the value is nil.

[show source]
# File lib/sequel/core.rb, line 212
def self.recursive_map(array, converter) do |i|
    if i.is_a?(Array)
      recursive_map(i, converter)
    elsif !i.nil?
require (files, subdir=nil)

Require all given files which should be in the same or a subdirectory of this file. If a subdir is given, assume all files are in that subdir. This is used to ensure that the files loaded are from the same version of Sequel as this file.

[show source]
# File lib/sequel/core.rb, line 226
def self.require(files, subdir=nil)
  Array(files).each{|f| super("#{File.dirname(__FILE__).untaint}/#{"#{subdir}/" if subdir}#{f}")}
split_symbol (sym)

Splits the symbol into three parts, if symbol splitting is enabled. Each part will either be a string or nil. If symbol splitting is disabled, returns an array with the first and third parts being nil, and the second part beind a string version of the symbol.

For columns, these parts are the table, column, and alias. For tables, these parts are the schema, table, and alias.

[show source]
# File lib/sequel/core.rb, line 239
def self.split_symbol(sym)
  unless v = Sequel.synchronize{SPLIT_SYMBOL_CACHE[sym]}
    if split = split_symbols?
      v = case s = sym.to_s
      when /\A((?:(?!__).)+)__((?:(?!___).)+)___(.+)\z/
        if split == :deprecated
          Sequel::Deprecation.deprecate("Symbol splitting", "Either set Sequel.split_symbols = true, or change #{sym.inspect} to Sequel.qualify(#{$1.inspect}, #{$2.inspect}).as(#{$3.inspect})")
        [$1.freeze, $2.freeze, $3.freeze].freeze
      when /\A((?:(?!___).)+)___(.+)\z/
        if split == :deprecated
          Sequel::Deprecation.deprecate("Symbol splitting", "Either set Sequel.split_symbols = true, or change #{sym.inspect} to Sequel.identifier(#{$1.inspect}).as(#{$2.inspect})")
        [nil, $1.freeze, $2.freeze].freeze
      when /\A((?:(?!__).)+)__(.+)\z/
        if split == :deprecated
          Sequel::Deprecation.deprecate("Symbol splitting", "Either set Sequel.split_symbols = true, or change #{sym.inspect} to Sequel.qualify(#{$1.inspect}, #{$2.inspect})")
        [$1.freeze, $2.freeze, nil].freeze
        [nil, s.freeze, nil].freeze
      v = [nil,sym.to_s.freeze,nil].freeze
    Sequel.synchronize{SPLIT_SYMBOL_CACHE[sym] = v}
split_symbols= (v)

Sequel by default will split symbols, treating:

:table__column         # table.column
:column___alias        # column AS alias
:table__column___alias # table.column AS alias

This can cause problems if any identifiers in the database use a double or triple underscore. When Sequel was first created, using symbols with double or triple underscores was the only way to represent qualified or aliased identifiers. Sequel now offers many ways to create qualified and aliased identifiers, so there is less of a need for this now. This allows you to turn off symbol splitting, potentially avoiding problems if you have identifiers that use double underscores:

Sequel.split_symbols = false

Note that Sequel::Database instances do their own caching of literalized symbols, and changing this setting does not affect those caches. It is recommended that if you want to change this setting, you do so directly after requiring Sequel, before creating any Sequel::Database instances.

Also note that disabling symbol splitting will also disable the handling of double underscores in virtual row methods, causing such methods to yield regular identifers instead of qualified identifiers. To make sure the code works when splitting symbols is both disabled and enabled, you can use Sequel::SQL::QualifyingMethods#[].

# Sequel.split_symbols = true
Sequel.expr{table__column}  # table.column
Sequel.expr{table[:column]} # table.column

# Sequel.split_symbols = false
Sequel.expr{table__column}  # table__column
Sequel.expr{table[:column]} # table.column
[show source]
# File lib/sequel/core.rb, line 303
def self.split_symbols=(v)
  @split_symbols = v
split_symbols? ()

Whether Sequel currently splits symbols into qualified/aliased identifiers.

[show source]
# File lib/sequel/core.rb, line 309
def self.split_symbols?
string_to_date (string)

Converts the given string into a Date object.

Sequel.string_to_date('2010-09-10') # Date.civil(2010, 09, 10)
[show source]
# File lib/sequel/core.rb, line 316
def self.string_to_date(string)
    Date.parse(string, Sequel.convert_two_digit_years)
  rescue => e
    raise convert_exception_class(e, InvalidValue)
string_to_datetime (string)

Converts the given string into a Time or DateTime object, depending on the value of Sequel.datetime_class.

Sequel.string_to_datetime('2010-09-10 10:20:30') # Time.local(2010, 09, 10, 10, 20, 30)
[show source]
# File lib/sequel/core.rb, line 328
def self.string_to_datetime(string)
    if datetime_class == DateTime
      DateTime.parse(string, convert_two_digit_years)
  rescue => e
    raise convert_exception_class(e, InvalidValue)
string_to_time (string)

Converts the given string into a Sequel::SQLTime object.

v = Sequel.string_to_time('10:20:30') # Sequel::SQLTime.parse('10:20:30')
DB.literal(v) # => '10:20:30'
[show source]
# File lib/sequel/core.rb, line 344
def self.string_to_time(string)
  rescue => e
    raise convert_exception_class(e, InvalidValue)
synchronize (&block)

Unless in single threaded mode, protects access to any mutable global data structure in Sequel. Uses a non-reentrant mutex, so calling code should be careful.

[show source]
# File lib/sequel/core.rb, line 358
def self.synchronize(&block)
  @single_threaded ? yield : @data_mutex.synchronize(&block)
transaction (dbs, opts=OPTS, &block)

Uses a transaction on all given databases with the given options. This:

Sequel.transaction([DB1, DB2, DB3]){}

is equivalent to:

DB1.transaction do
  DB2.transaction do
    DB3.transaction do

except that if Sequel::Rollback is raised by the block, the transaction is rolled back on all databases instead of just the last one.

Note that this method cannot guarantee that all databases will commit or rollback. For example, if DB3 commits but attempting to commit on DB2 fails (maybe because foreign key checks are deferred), there is no way to uncommit the changes on DB3. For that kind of support, you need to have two-phase commit/prepared transactions (which Sequel supports on some databases).

[show source]
# File lib/sequel/core.rb, line 384
def self.transaction(dbs, opts=OPTS, &block)
  unless opts[:rollback]
    rescue_rollback = true
    opts = Hash[opts].merge!(:rollback=>:reraise)
  pr = dbs.reverse.inject(block){|bl, db| proc{db.transaction(opts, &bl)}}
  if rescue_rollback
    rescue Sequel::Rollback
version ()

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

[show source]
# File lib/sequel/version.rb, line 16
def self.version
virtual_row (&block)

If the supplied block takes a single argument, yield an SQL::VirtualRow instance to the block argument. Otherwise, evaluate the block in the context of a SQL::VirtualRow instance.

Sequel.virtual_row{a} #
Sequel.virtual_row{|o| o.a} #
[show source]
# File lib/sequel/core.rb, line 408
def self.virtual_row(&block)
  case block.arity
  when -1, 0