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 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.

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 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 = 26  

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 Sequel.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
77 def self.condition_specifier?(obj)
78   case obj
79   when Hash
80     true
81   when Array
82     !obj.empty? && !obj.is_a?(SQL::ValueList) && obj.all?{|i| i.is_a?(Array) && (i.length == 2)}
83   else
84     false
85   end
86 end
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
120 def self.connect(*args, &block)
121   Database.connect(*args, &block)
122 end
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
133 def self.convert_exception_class(exception, klass)
134   return exception if exception.is_a?(klass)
135   e ="#{exception.class}: #{exception.message}")
136   e.wrapped_exception = exception
137   e.set_backtrace(exception.backtrace)
138   e
139 end
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
126 def self.core_extensions?
127   false
128 end
elapsed_seconds_since (timer)

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

[show source]
    # File lib/sequel/core.rb
327 def self.elapsed_seconds_since(timer)
328   start_timer - timer
329 end
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
149 def self.extension(*extensions)
150   extensions.each{|e| orig_require("sequel/extensions/#{e}")}
151 end
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 block_given?
8   Inflections
9 end
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
155 def self.json_parser_error_class
156   JSON::ParserError
157 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

  down do

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

[show source]
    # File lib/sequel/extensions/migration.rb
288 def self.migration(&block)
289   MigrationDSL.create(&block)
290 end
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
161 def self.object_to_json(obj, *args, &block)
162   obj.to_json(*args, &block)
163 end
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
167 def self.parse_json(json)
168   JSON.parse(json, :create_additions=>false)
169 end
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
174 def self.recursive_map(array, converter)
175 do |i|
176     if i.is_a?(Array)
177       recursive_map(i, converter)
178     elsif !i.nil?
180     end
181   end
182 end
require (files, subdir=nil)

For backwards compatibility only. require_relative should be used instead.

[show source]
    # File lib/sequel/core.rb
185 def self.require(files, subdir=nil)
186   # Use Kernel.require_relative to work around JRuby 9.0 bug
187   Array(files).each{|f| Kernel.require_relative "#{"#{subdir}/" if subdir}#{f}"}
188 end
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
199 def self.split_symbol(sym)
200   unless v = Sequel.synchronize{SPLIT_SYMBOL_CACHE[sym]}
201     if split_symbols?
202       v = case s = sym.to_s
203       when /\A((?:(?!__).)+)__((?:(?!___).)+)___(.+)\z/
204         [$1.freeze, $2.freeze, $3.freeze].freeze
205       when /\A((?:(?!___).)+)___(.+)\z/
206         [nil, $1.freeze, $2.freeze].freeze
207       when /\A((?:(?!__).)+)__(.+)\z/
208         [$1.freeze, $2.freeze, nil].freeze
209       else
210         [nil, s.freeze, nil].freeze
211       end
212     else
213       v = [nil,sym.to_s.freeze,nil].freeze
214     end
215     Sequel.synchronize{SPLIT_SYMBOL_CACHE[sym] = v}
216   end
217   v
218 end
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
250 def self.split_symbols=(v)
251   Sequel.synchronize{SPLIT_SYMBOL_CACHE.clear}
252   @split_symbols = v
253 end
split_symbols? ()

Whether Sequel currently splits symbols into qualified/aliased identifiers.

[show source]
    # File lib/sequel/core.rb
256 def self.split_symbols?
257   @split_symbols
258 end
start_timer ()

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

[show source]
    # File lib/sequel/core.rb
314 def self.start_timer
315   Process.clock_gettime(Process::CLOCK_MONOTONIC)
316 end
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
263 def self.string_to_date(string)
264   begin
265     Date.parse(string, Sequel.convert_two_digit_years)
266   rescue => e
267     raise convert_exception_class(e, InvalidValue)
268   end
269 end
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
275 def self.string_to_datetime(string)
276   begin
277     if datetime_class == DateTime
278       DateTime.parse(string, convert_two_digit_years)
279     else
280       datetime_class.parse(string)
281     end
282   rescue => e
283     raise convert_exception_class(e, InvalidValue)
284   end
285 end
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
291 def self.string_to_time(string)
292   begin
293     SQLTime.parse(string)
294   rescue => e
295     raise convert_exception_class(e, InvalidValue)
296   end
297 end
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
307 def self.synchronize(&block)
308   @single_threaded ? yield : @data_mutex.synchronize(&block)
309 end
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
353 def self.transaction(dbs, opts=OPTS, &block)
354   unless opts[:rollback]
355     rescue_rollback = true
356     opts = Hash[opts].merge!(:rollback=>:reraise)
357   end
358   pr = dbs.reverse.inject(block){|bl, db| proc{db.transaction(opts, &bl)}}
359   if rescue_rollback
360     begin
362     rescue Sequel::Rollback
363       nil
364     end
365   else
367   end
368 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
24 end
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
377 def self.virtual_row(&block)
378   vr = VIRTUAL_ROW
379   case block.arity
380   when -1, 0
381     vr.instance_exec(&block)
382   else
384   end  
385 end