Module: Sequel

Defined in:
lib/sequel/core.rb,
lib/sequel/sql.rb,
lib/sequel/model.rb,
lib/sequel/dataset.rb,
lib/sequel/version.rb,
lib/sequel/database.rb,
lib/sequel/migration.rb,
lib/sequel/deprecated.rb,
lib/sequel/exceptions.rb,
lib/sequel/model/base.rb,
lib/sequel/adapters/do.rb,
lib/sequel/dataset/sql.rb,
lib/sequel/adapters/ado.rb,
lib/sequel/adapters/db2.rb,
lib/sequel/adapters/dbi.rb,
lib/sequel/model/errors.rb,
lib/sequel/object_graph.rb,
lib/sequel/adapters/jdbc.rb,
lib/sequel/adapters/odbc.rb,
lib/sequel/model/plugins.rb,
lib/sequel/adapters/mysql.rb,
lib/sequel/plugins/schema.rb,
lib/sequel/adapters/oracle.rb,
lib/sequel/adapters/sqlite.rb,
lib/sequel/metaprogramming.rb,
lib/sequel/plugins/caching.rb,
lib/sequel/adapters/jdbc/h2.rb,
lib/sequel/extensions/query.rb,
lib/sequel/model/deprecated.rb,
lib/sequel/model/exceptions.rb,
lib/sequel/adapters/do/mysql.rb,
lib/sequel/adapters/firebird.rb,
lib/sequel/adapters/informix.rb,
lib/sequel/adapters/openbase.rb,
lib/sequel/adapters/postgres.rb,
lib/sequel/model/inflections.rb,
lib/sequel/adapters/do/sqlite.rb,
lib/sequel/model/associations.rb,
lib/sequel/adapters/jdbc/mysql.rb,
lib/sequel/database/schema_sql.rb,
lib/sequel/dataset/convenience.rb,
lib/sequel/adapters/do/postgres.rb,
lib/sequel/adapters/jdbc/oracle.rb,
lib/sequel/adapters/jdbc/sqlite.rb,
lib/sequel/adapters/shared/mssql.rb,
lib/sequel/adapters/shared/mysql.rb,
lib/sequel/extensions/pagination.rb,
lib/sequel/adapters/shared/oracle.rb,
lib/sequel/adapters/shared/sqlite.rb,
lib/sequel/model/deprecated_hooks.rb,
lib/sequel/database/schema_methods.rb,
lib/sequel/extensions/pretty_table.rb,
lib/sequel/adapters/jdbc/postgresql.rb,
lib/sequel/adapters/shared/progress.rb,
lib/sequel/database/schema_generator.rb,
lib/sequel/plugins/hook_class_methods.rb,
lib/sequel/dataset/prepared_statements.rb,
lib/sequel/model/deprecated_validations.rb,
lib/sequel/adapters/utils/stored_procedures.rb,
lib/sequel/plugins/single_table_inheritance.rb,
lib/sequel/plugins/validation_class_methods.rb

Overview

Associations are used in order to specify relationships between model classes that reflect relations between tables in the database using foreign keys.

Each kind of association adds a number of methods to the model class which are specialized according to the association type and optional parameters given in the definition. Example:

class Project < Sequel::Model
  many_to_one :portfolio
  one_to_many :milestones
end

The project class now has the following instance methods:

  • portfolio - Returns the associated portfolio.

  • portfolio=(obj) - Sets the associated portfolio to the object, but the change is not persisted until you save the record.

  • portfolio_dataset - Returns a dataset that would return the associated portfolio, only useful in fairly specific circumstances.

  • milestones - Returns an array of associated milestones

  • add_milestone(obj) - Associates the passed milestone with this object.

  • remove_milestone(obj) - Removes the association with the passed milestone.

  • remove_all_milestones - Removes associations with all associated milestones.

  • milestones_dataset - Returns a dataset that would return the associated milestones, allowing for further filtering/limiting/etc.

If you want to override the behavior of the add_/remove_/remove_all_ methods, there are private instance methods created that a prepended with an underscore (e.g. _add_milestone). The private instance methods can be easily overridden, but you shouldn’t override the public instance methods, as they deal with how associations are cached.

By default the classes for the associations are inferred from the association name, so for example the Project#portfolio will return an instance of Portfolio, and Project#milestones will return an array of Milestone instances, in similar fashion to how ActiveRecord infers class names.

Association definitions are also reflected by the class, e.g.:

Project.associations
=> [:portfolio, :milestones]
Project.association_reflection(:portfolio)
=> {:type => :many_to_one, :name => :portfolio, :class_name => "Portfolio"}

Associations can be defined by either using the associate method, or by calling one of the three methods: many_to_one, one_to_many, many_to_many. Sequel::Model also provides aliases for these methods that conform to ActiveRecord conventions: belongs_to, has_many, has_and_belongs_to_many. For example, the following three statements are equivalent:

associate :one_to_many, :attributes
one_to_many :attributes
has_many :attributes

Defined Under Namespace

Modules: ADO, DB2, DBI, DataObjects, Deprecation, Firebird, Inflections, Informix, JDBC, MSSQL, Metaprogramming, Migrator, MySQL, ODBC, OpenBase, Oracle, Plugins, Postgres, PrettyTable, Progress, SQL, SQLite, Schema Classes: BeforeHookFailed, ConnectionPool, Database, DatabaseConnectionError, DatabaseDisconnectError, DatabaseError, Dataset, Error, LiteralString, Migration, Model, SingleThreadedPool, ValidationFailed

Constant Summary collapse

MAJOR = 
2
MINOR = 
11
TINY = 
0
VERSION = 
[MAJOR, MINOR, TINY].join('.')
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 they will not get garbage collected.

[]

Class Attribute Summary collapse

Class Method Summary collapse

Class Attribute Details

.convert_tinyint_to_bool ⇒ Object

Returns the value of attribute convert_tinyint_to_bool.



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# File 'lib/sequel/core.rb', line 63

def convert_tinyint_to_bool
  @convert_tinyint_to_bool
end

.convert_two_digit_years ⇒ Object

Returns the value of attribute convert_two_digit_years.



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# File 'lib/sequel/core.rb', line 63

def convert_two_digit_years
  @convert_two_digit_years
end

.datetime_class ⇒ Object

Returns the value of attribute datetime_class.



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# File 'lib/sequel/core.rb', line 63

def datetime_class
  @datetime_class
end

.virtual_row_instance_eval ⇒ Object

Returns the value of attribute virtual_row_instance_eval.



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# File 'lib/sequel/core.rb', line 63

def virtual_row_instance_eval
  @virtual_row_instance_eval
end

Class Method Details

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

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}



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# File 'lib/sequel/core.rb', line 81

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

.identifier_input_method=(value) ⇒ Object

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 methods work as well.



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# File 'lib/sequel/core.rb', line 96

def self.identifier_input_method=(value)
  Database.identifier_input_method = value
end

.identifier_output_method=(value) ⇒ Object

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 methods work as well.



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# File 'lib/sequel/core.rb', line 112

def self.identifier_output_method=(value)
  Database.identifier_output_method = value
end

.inflections {|Inflections| ... } ⇒ Object

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

Yields:



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# File 'lib/sequel/model/inflections.rb', line 4

def self.inflections
  yield Inflections if block_given?
  Inflections
end

.Model(source) ⇒ Object

Lets you create a Model subclass with its dataset already set. source can be an existing dataset or a symbol (in which case it will create a dataset using the default database with source as the table name).

Example:

class Comment < Sequel::Model(:something)
  table_name # => :something
end



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# File 'lib/sequel/model.rb', line 18

def self.Model(source)
  @models[source] ||= Class.new(Model).set_dataset(source)
end

.open(*args, &block) ⇒ Object 



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# File 'lib/sequel/deprecated.rb', line 39

def self.open(*args, &block)
  Deprecation.deprecate('Sequel.open', 'Use Sequel.connect')
  Database.connect(*args, &block)
end

.quote_identifiers=(value) ⇒ Object

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



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# File 'lib/sequel/core.rb', line 120

def self.quote_identifiers=(value)
  Database.quote_identifiers = value
end

.require(files, subdir = nil) ⇒ Object

Require all given files which should be in the same or a subdirectory of this file



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# File 'lib/sequel/core.rb', line 126

def self.require(files, subdir=nil)
  Array(files).each{|f| super("#{File.dirname(__FILE__)}/#{"#{subdir}/" if subdir}#{f}")}
end

.single_threaded=(value) ⇒ Object

Set whether to set the single threaded mode for all databases by default. By default, Sequel uses a threadsafe connection pool, which isn’t as fast as the single threaded connection pool. If your program will only have one thread, and speed is a priority, you may want to set this to true:

Sequel.single_threaded = true



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# File 'lib/sequel/core.rb', line 136

def self.single_threaded=(value)
  Database.single_threaded = value
end

.string_to_date(s) ⇒ Object

Converts a string into a Date object.



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# File 'lib/sequel/core.rb', line 141

def self.string_to_date(s)
  begin
    Date.parse(s, Sequel.convert_two_digit_years)
  rescue => e
    raise Error::InvalidValue, "Invalid Date value '#{self}' (#{e.message})"
  end
end

.string_to_datetime(s) ⇒ Object

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



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# File 'lib/sequel/core.rb', line 151

def self.string_to_datetime(s)
  begin
    if datetime_class == DateTime
      DateTime.parse(s, convert_two_digit_years)
    else
      datetime_class.parse(s)
    end
  rescue => e
    raise Error::InvalidValue, "Invalid #{datetime_class} value '#{self}' (#{e.message})"
  end
end

.string_to_time(s) ⇒ Object

Converts a string into a Time object.



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

def self.string_to_time(s)
  begin
    Time.parse(s)
  rescue => e
    raise Error::InvalidValue, "Invalid Time value '#{self}' (#{e.message})"
  end
end

.upcase_identifiers=(value) ⇒ Object 



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# File 'lib/sequel/deprecated.rb', line 44

def self.upcase_identifiers=(value)
  Deprecation.deprecate('Sequel.upcase_identifiers=', 'Use Sequel.identifier_input_method = :upcase or nil')
  Database.identifier_input_method = value ? :upcase : nil
end

.use_parse_tree ⇒ Object 



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# File 'lib/sequel/deprecated.rb', line 49

def self.use_parse_tree
  Deprecation.deprecate('Sequel.use_parse_tree', 'Sequel has not used ParseTree since 2.2')
  false
end

.use_parse_tree=(val) ⇒ Object

Raises:



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# File 'lib/sequel/deprecated.rb', line 54

def self.use_parse_tree=(val)
  Deprecation.deprecate('Sequel.use_parse_tree=', 'Sequel has not used ParseTree since 2.2')
  raise(Error, 'ParseTree support has been removed from Sequel') if val
end

.version ⇒ Object 



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# File 'lib/sequel/version.rb', line 8

def self.version
  VERSION
end