Module: Sequel::SequelMethods

Included in:
Sequel
Defined in:
lib/sequel/timezones.rb,
lib/sequel/core.rb

Overview

Sequel doesn't pay much attention to timezones by default, but you can set it handle timezones if you want. There are three separate timezone settings, application_timezone, database_timezone, and typecast_timezone. All three timezones have getter and setter methods. You can set all three timezones to the same value at once via Sequel.default_timezone=.

The only timezone values that are supported by default are :utc (convert to UTC), :local (convert to local time), and nil (don't convert). If you need to convert to a specific timezone, or need the timezones being used to change based on the environment (e.g. current user), you need to use the named_timezones extension (and use DateTime as the datetime_class). Sequel also ships with a thread_local_timezones extensions which allows each thread to have its own timezone values for each of the timezones.

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#application_timezoneObject (readonly)

The timezone you want the application to use. This is the timezone that incoming times from the database and typecasting are converted to.


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# File 'lib/sequel/timezones.rb', line 27

def application_timezone
  @application_timezone
end

#convert_two_digit_yearsObject

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

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# File 'lib/sequel/core.rb', line 48

def convert_two_digit_years
  @convert_two_digit_years
end

#database_timezoneObject (readonly)

The timezone for storage in the database. This is the timezone to which Sequel will convert timestamps before literalizing them for storage in the database. It is also the timezone that Sequel will assume database timestamp values are already in (if they don't include an offset).


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# File 'lib/sequel/timezones.rb', line 33

def database_timezone
  @database_timezone
end

#datetime_classObject

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).


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# File 'lib/sequel/core.rb', line 59

def datetime_class
  @datetime_class
end

#single_threadedObject

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

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# File 'lib/sequel/core.rb', line 68

def single_threaded
  @single_threaded
end

#typecast_timezoneObject (readonly)

The timezone that incoming data that Sequel needs to typecast is assumed to be already in (if they don't include an offset).


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# File 'lib/sequel/timezones.rb', line 37

def typecast_timezone
  @typecast_timezone
end

Instance Method Details

#application_to_database_timestamp(v) ⇒ Object

Convert the given Time/DateTime object into the database timezone, used when literalizing objects in an SQL string.


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# File 'lib/sequel/timezones.rb', line 45

def application_to_database_timestamp(v)
  convert_output_timestamp(v, Sequel.database_timezone)
end

#condition_specifier?(obj) ⇒ Boolean

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

Returns:

  • (Boolean)

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# File 'lib/sequel/core.rb', line 84

def condition_specifier?(obj)
  case obj
  when Hash
    true
  when Array
    !obj.empty? && !obj.is_a?(SQL::ValueList) && obj.all?{|i| i.is_a?(Array) && (i.length == 2)}
  else
    false
  end
end

#connect(*args, &block) ⇒ Object

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:[email protected]: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.


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# File 'lib/sequel/core.rb', line 124

def connect(*args, &block)
  Database.connect(*args, &block)
end

#convert_exception_class(exception, klass) ⇒ Object

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.


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# File 'lib/sequel/core.rb', line 137

def convert_exception_class(exception, klass)
  return exception if exception.is_a?(klass)
  e = klass.new("#{exception.class}: #{exception.message}")
  e.wrapped_exception = exception
  e.set_backtrace(exception.backtrace)
  e
end

#convert_output_timestamp(v, output_timezone) ⇒ Object

Converts the object to the given output_timezone.


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# File 'lib/sequel/timezones.rb', line 50

def convert_output_timestamp(v, output_timezone)
  if output_timezone
    if v.is_a?(DateTime)
      case output_timezone
      when :utc
        v.new_offset(0)
      when :local
        v.new_offset(local_offset_for_datetime(v))
      else
        convert_output_datetime_other(v, output_timezone)
      end
    else
      case output_timezone
      when :utc
        v.getutc
      when :local
        v.getlocal
      else
        convert_output_time_other(v, output_timezone)
      end
    end
  else
    v
  end
end

#convert_timestamp(v, input_timezone) ⇒ Object

Converts the given object from the given input timezone to the application_timezone using convert_input_timestamp and convert_output_timestamp.


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# File 'lib/sequel/timezones.rb', line 79

def convert_timestamp(v, input_timezone)
  begin
    if v.is_a?(Date) && !v.is_a?(DateTime)
      # Dates handled specially as they are assumed to already be in the application_timezone
      if datetime_class == DateTime
        DateTime.civil(v.year, v.month, v.day, 0, 0, 0, application_timezone == :local ? Rational(Time.local(v.year, v.month, v.day).utc_offset, 86400) : 0)
      else
        Time.public_send(application_timezone == :utc ? :utc : :local, v.year, v.month, v.day)
      end
    else
      convert_output_timestamp(convert_input_timestamp(v, input_timezone), application_timezone)
    end
  rescue InvalidValue
    raise
  rescue => e
    raise convert_exception_class(e, InvalidValue)
  end
end

#core_extensions?Boolean

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

Returns:

  • (Boolean)

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# File 'lib/sequel/core.rb', line 130

def core_extensions?
  false
end

#currentObject

The current concurrency primitive, Thread.current by default.


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# File 'lib/sequel/core.rb', line 146

def current
  Thread.current
end

#database_to_application_timestamp(v) ⇒ Object

Convert the given object into an object of Sequel.datetime_class in the application_timezone. Used when converting datetime/timestamp columns returned by the database.


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# File 'lib/sequel/timezones.rb', line 101

def database_to_application_timestamp(v)
  convert_timestamp(v, Sequel.database_timezone)
end

#default_timezone=(tz) ⇒ Object

Sets the database, application, and typecasting timezones to the given timezone.


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# File 'lib/sequel/timezones.rb', line 106

def default_timezone=(tz)
  self.database_timezone = tz
  self.application_timezone = tz
  self.typecast_timezone = tz
end

#elapsed_seconds_since(timer) ⇒ Object

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


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# File 'lib/sequel/core.rb', line 331

def elapsed_seconds_since(timer)
  start_timer - timer
end

#extension(*extensions) ⇒ Object

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(:blank)
Sequel.extension(:core_extensions, :named_timezones)

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# File 'lib/sequel/core.rb', line 158

def extension(*extensions)
  extensions.each{|e| orig_require("sequel/extensions/#{e}")}
end

#json_parser_error_classObject

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


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# File 'lib/sequel/core.rb', line 164

def json_parser_error_class
  JSON::ParserError
end

#object_to_json(obj, *args, &block) ⇒ Object

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


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# File 'lib/sequel/core.rb', line 170

def object_to_json(obj, *args, &block)
  obj.to_json(*args, &block)
end

#parse_json(json) ⇒ Object

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


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# File 'lib/sequel/core.rb', line 176

def parse_json(json)
  JSON.parse(json, :create_additions=>false)
end

#recursive_map(array, converter) ⇒ Object

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.


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# File 'lib/sequel/core.rb', line 183

def recursive_map(array, converter)
  array.map do |i|
    if i.is_a?(Array)
      recursive_map(i, converter)
    elsif !i.nil?
      converter.call(i)
    end
  end
end

#require(files, subdir = nil) ⇒ Object

For backwards compatibility only. require_relative should be used instead.


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# File 'lib/sequel/core.rb', line 194

def 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}"}
end

#split_symbol(sym) ⇒ Object

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.


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# File 'lib/sequel/core.rb', line 206

def 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
      else
        [nil, s.freeze, nil].freeze
      end
    else
      v = [nil,sym.to_s.freeze,nil].freeze
    end
    Sequel.synchronize{SPLIT_SYMBOL_CACHE[sym] = v}
  end
  v
end

#split_symbols=(v) ⇒ Object

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

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# File 'lib/sequel/core.rb', line 257

def split_symbols=(v)
  Sequel.synchronize{SPLIT_SYMBOL_CACHE.clear}
  @split_symbols = v
end

#split_symbols?Boolean

Whether Sequel currently splits symbols into qualified/aliased identifiers.

Returns:

  • (Boolean)

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# File 'lib/sequel/core.rb', line 263

def split_symbols?
  @split_symbols
end

#start_timerObject

:nocov:


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# File 'lib/sequel/core.rb', line 318

def start_timer
  Process.clock_gettime(Process::CLOCK_MONOTONIC)
end

#string_to_date(string) ⇒ Object

Converts the given string into a Date object.

Sequel.string_to_date('2010-09-10') # Date.civil(2010, 09, 10)

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# File 'lib/sequel/core.rb', line 270

def string_to_date(string)
  begin
    Date.parse(string, Sequel.convert_two_digit_years)
  rescue => e
    raise convert_exception_class(e, InvalidValue)
  end
end

#string_to_datetime(string) ⇒ Object

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)

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# File 'lib/sequel/core.rb', line 282

def string_to_datetime(string)
  begin
    if datetime_class == DateTime
      DateTime.parse(string, convert_two_digit_years)
    else
      datetime_class.parse(string)
    end
  rescue => e
    raise convert_exception_class(e, InvalidValue)
  end
end

#string_to_time(string) ⇒ Object

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'

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# File 'lib/sequel/core.rb', line 298

def string_to_time(string)
  begin
    SQLTime.parse(string)
  rescue => e
    raise convert_exception_class(e, InvalidValue)
  end
end

#synchronize(&block) ⇒ Object

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.


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# File 'lib/sequel/core.rb', line 311

def synchronize(&block)
  @single_threaded ? yield : @data_mutex.synchronize(&block)
end

#transaction(dbs, opts = OPTS, &block) ⇒ Object

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
    end
  end
end

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).


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# File 'lib/sequel/core.rb', line 357

def transaction(dbs, opts=OPTS, &block)
  unless opts[:rollback]
    rescue_rollback = true
    opts = Hash[opts].merge!(:rollback=>:reraise)
  end
  pr = dbs.reverse.inject(block){|bl, db| proc{db.transaction(opts, &bl)}}
  if rescue_rollback
    begin
      pr.call
    rescue Sequel::Rollback
      nil
    end
  else
    pr.call
  end
end

#typecast_to_application_timestamp(v) ⇒ Object

Convert the given object into an object of Sequel.datetime_class in the application_timezone. Used when typecasting values when assigning them to model datetime attributes.


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# File 'lib/sequel/timezones.rb', line 115

def typecast_to_application_timestamp(v)
  convert_timestamp(v, Sequel.typecast_timezone)
end

#virtual_row(&block) ⇒ Object

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::SQL::Identifier.new(:a)
Sequel.virtual_row{|o| o.a} # Sequel::SQL::Function.new(:a)

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# File 'lib/sequel/core.rb', line 381

def virtual_row(&block)
  vr = VIRTUAL_ROW
  case block.arity
  when -1, 0
    vr.instance_exec(&block)
  else
    block.call(vr)
  end  
end