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/placeholder_literalizer.rb
  26. lib/sequel/dataset/prepared_statements.rb
  27. lib/sequel/dataset/query.rb
  28. lib/sequel/dataset/sql.rb
  29. lib/sequel/deprecated.rb
  30. lib/sequel/exceptions.rb
  31. lib/sequel/extensions/migration.rb
  32. lib/sequel/model.rb
  33. lib/sequel/model/associations.rb
  34. lib/sequel/model/base.rb
  35. lib/sequel/model/dataset_module.rb
  36. lib/sequel/model/default_inflections.rb
  37. lib/sequel/model/errors.rb
  38. lib/sequel/model/exceptions.rb
  39. lib/sequel/model/inflections.rb
  40. lib/sequel/model/plugins.rb
  41. lib/sequel/sql.rb
  42. lib/sequel/timezones.rb
  43. lib/sequel/version.rb
  44. 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',
       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 ::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.

Included modules

  1. SQL::Constants



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.

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 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 =  

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.

DatabaseLockTimeout =  

Error raised when Sequel determines the database could not acquire a necessary lock before timing out. Use of Sequel::Dataset#nowait can often cause this exception when retrieving rows.

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 when the database does not support that.

InvalidValue =  

Error raised when attempting an invalid type conversion.

MAJOR = 5  

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

MINOR = 15  

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.

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”)


The version of Sequel you are using, as a number (2.11.0 -> 20110)


Public Class Aliases

orig_require -> require

Alias of original require method, as ::require is does a relative require for backwards compatibility.


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

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

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 76
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, or use the keep_reference: false Database option.

For details, see the “Connecting to a Database” guide. To set up a primary/replica or sharded database connection, see the “Primary/Replica Database Configurations and Sharding” guide.

[show source]
# File lib/sequel/core.rb, line 119
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 132
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 125
def self.core_extensions?
elapsed_seconds_since (timer)

The elapsed seconds since the given timer object was created. The timer object should have been created via ::start_timer.

[show source]
# File lib/sequel/core.rb, line 326
def self.elapsed_seconds_since(timer)
  start_timer - timer
extension (*extensions)

Load all Sequel extensions given. Extensions are just files that exist under sequel/extensions in the load path, and are just required.

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 148
def self.extension(*extensions)
  extensions.each{|e| orig_require("sequel/extensions/#{e}")}
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 154
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 287
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 160
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 166
def self.parse_json(json)
  JSON.parse(json, :create_additions=>false)
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 173
def self.recursive_map(array, converter) do |i|
    if i.is_a?(Array)
      recursive_map(i, converter)
    elsif !i.nil?
require (files, subdir=nil)

For backwards compatibility only. require_relative should be used instead.

[show source]
# File lib/sequel/core.rb, line 184
def self.require(files, subdir=nil)
  # Use Kernel.require_relative to work around JRuby 9.0 bug
  Array(files).each{|f| Kernel.require_relative "#{"#{subdir}/" if subdir}#{f}"}
split_symbol (sym)

Splits the symbol into three parts, if symbol splitting is enabled (not the default). 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 198
def self.split_symbol(sym)
  unless v = Sequel.synchronize{SPLIT_SYMBOL_CACHE[sym]}
    if split_symbols?
      v = case s = sym.to_s
      when /\A((?:(?!__).)+)__((?:(?!___).)+)___(.+)\z/
        [$1.freeze, $2.freeze, $3.freeze].freeze
      when /\A((?:(?!___).)+)___(.+)\z/
        [nil, $1.freeze, $2.freeze].freeze
      when /\A((?:(?!__).)+)__(.+)\z/
        [$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)

Setting this to true enables Sequel's historical behavior of splitting symbols on double or triple underscores:

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

It is only recommended to turn this on for backwards compatibility until such symbols have been converted to use newer Sequel APIs such as:

Sequel[:table][:column]            # table.column
Sequel[:column].as(:alias)         # column AS alias
Sequel[:table][:column].as(:alias) # table.column AS alias

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.

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:

# 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 249
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 255
def self.split_symbols?
start_timer ()

A timer object that can be passed to ::elapsed_seconds_since to return the number of seconds elapsed.

[show source]
# File lib/sequel/core.rb, line 313
def self.start_timer
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 262
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 274
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 290
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. In general, this should only be used around the minimal possible code such as Hash#[], Hash#[]=, Hash#delete, Array#<<, and Array#delete.

[show source]
# File lib/sequel/core.rb, line 306
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 352
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 21
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 376
def self.virtual_row(&block)
  case block.arity
  when -1, 0