Module: Sequel

Extended by:
EvalInspect, NamedTimezones, SQL::Builders, SQL::OperatorBuilders, ThreadLocalTimezones, Timezones
Includes:
SQL::Constants
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/timezones.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/dataset/misc.rb,
lib/sequel/model/errors.rb,
lib/sequel/plugins/list.rb,
lib/sequel/plugins/tree.rb,
lib/sequel/plugins/uuid.rb,
lib/sequel/adapters/jdbc.rb,
lib/sequel/adapters/mock.rb,
lib/sequel/adapters/odbc.rb,
lib/sequel/database/misc.rb,
lib/sequel/dataset/graph.rb,
lib/sequel/dataset/query.rb,
lib/sequel/model/plugins.rb,
lib/sequel/plugins/dirty.rb,
lib/sequel/plugins/touch.rb,
lib/sequel/adapters/ibmdb.rb,
lib/sequel/adapters/mysql.rb,
lib/sequel/adapters/swift.rb,
lib/sequel/database/query.rb,
lib/sequel/plugins/finder.rb,
lib/sequel/plugins/pg_row.rb,
lib/sequel/plugins/schema.rb,
lib/sequel/adapters/cubrid.rb,
lib/sequel/adapters/mysql2.rb,
lib/sequel/adapters/oracle.rb,
lib/sequel/adapters/sqlite.rb,
lib/sequel/ast_transformer.rb,
lib/sequel/dataset/actions.rb,
lib/sequel/plugins/caching.rb,
lib/sequel/adapters/jdbc/h2.rb,
lib/sequel/adapters/tinytds.rb,
lib/sequel/database/dataset.rb,
lib/sequel/database/logging.rb,
lib/sequel/dataset/features.rb,
lib/sequel/dataset/mutation.rb,
lib/sequel/extensions/query.rb,
lib/sequel/model/exceptions.rb,
lib/sequel/plugins/scissors.rb,
lib/sequel/plugins/sharding.rb,
lib/sequel/adapters/do/mysql.rb,
lib/sequel/adapters/jdbc/db2.rb,
lib/sequel/adapters/postgres.rb,
lib/sequel/database/features.rb,
lib/sequel/extensions/pg_row.rb,
lib/sequel/extensions/to_dot.rb,
lib/sequel/model/inflections.rb,
lib/sequel/plugins/rcte_tree.rb,
lib/sequel/adapters/ado/mssql.rb,
lib/sequel/adapters/jdbc/jtds.rb,
lib/sequel/extensions/pg_enum.rb,
lib/sequel/extensions/pg_inet.rb,
lib/sequel/extensions/pg_json.rb,
lib/sequel/model/associations.rb,
lib/sequel/plugins/eager_each.rb,
lib/sequel/plugins/subclasses.rb,
lib/sequel/plugins/timestamps.rb,
lib/sequel/adapters/ado/access.rb,
lib/sequel/adapters/amalgalite.rb,
lib/sequel/adapters/do/sqlite3.rb,
lib/sequel/adapters/jdbc/as400.rb,
lib/sequel/adapters/jdbc/derby.rb,
lib/sequel/adapters/jdbc/mssql.rb,
lib/sequel/adapters/jdbc/mysql.rb,
lib/sequel/adapters/odbc/mssql.rb,
lib/sequel/adapters/shared/db2.rb,
lib/sequel/database/connecting.rb,
lib/sequel/extensions/meta_def.rb,
lib/sequel/extensions/pg_array.rb,
lib/sequel/extensions/pg_range.rb,
lib/sequel/plugins/composition.rb,
lib/sequel/adapters/do/postgres.rb,
lib/sequel/adapters/jdbc/cubrid.rb,
lib/sequel/adapters/jdbc/hsqldb.rb,
lib/sequel/adapters/jdbc/oracle.rb,
lib/sequel/adapters/jdbc/sqlite.rb,
lib/sequel/adapters/sqlanywhere.rb,
lib/sequel/adapters/swift/mysql.rb,
lib/sequel/extensions/error_sql.rb,
lib/sequel/extensions/migration.rb,
lib/sequel/extensions/pg_hstore.rb,
lib/sequel/model/dataset_module.rb,
lib/sequel/plugins/active_model.rb,
lib/sequel/plugins/split_values.rb,
lib/sequel/plugins/static_cache.rb,
lib/sequel/plugins/table_select.rb,
lib/sequel/adapters/shared/mssql.rb,
lib/sequel/adapters/shared/mysql.rb,
lib/sequel/adapters/swift/sqlite.rb,
lib/sequel/database/transactions.rb,
lib/sequel/extensions/from_block.rb,
lib/sequel/extensions/graph_each.rb,
lib/sequel/extensions/pagination.rb,
lib/sequel/extensions/pg_row_ops.rb,
lib/sequel/extensions/string_agg.rb,
lib/sequel/plugins/column_select.rb,
lib/sequel/plugins/serialization.rb,
lib/sequel/adapters/shared/access.rb,
lib/sequel/adapters/shared/cubrid.rb,
lib/sequel/adapters/shared/oracle.rb,
lib/sequel/adapters/shared/sqlite.rb,
lib/sequel/adapters/utils/replace.rb,
lib/sequel/extensions/pg_inet_ops.rb,
lib/sequel/extensions/pg_interval.rb,
lib/sequel/extensions/pg_json_ops.rb,
lib/sequel/plugins/csv_serializer.rb,
lib/sequel/plugins/error_splitter.rb,
lib/sequel/plugins/force_encoding.rb,
lib/sequel/plugins/instance_hooks.rb,
lib/sequel/plugins/update_refresh.rb,
lib/sequel/plugins/xml_serializer.rb,
lib/sequel/adapters/jdbc/sqlserver.rb,
lib/sequel/adapters/swift/postgres.rb,
lib/sequel/database/schema_methods.rb,
lib/sequel/extensions/eval_inspect.rb,
lib/sequel/extensions/hash_aliases.rb,
lib/sequel/extensions/null_dataset.rb,
lib/sequel/extensions/pg_array_ops.rb,
lib/sequel/extensions/pg_range_ops.rb,
lib/sequel/extensions/pretty_table.rb,
lib/sequel/extensions/server_block.rb,
lib/sequel/extensions/sql_comments.rb,
lib/sequel/plugins/association_pks.rb,
lib/sequel/plugins/boolean_readers.rb,
lib/sequel/plugins/boolean_subsets.rb,
lib/sequel/plugins/columns_updated.rb,
lib/sequel/plugins/defaults_setter.rb,
lib/sequel/plugins/json_serializer.rb,
lib/sequel/plugins/lazy_attributes.rb,
lib/sequel/plugins/string_stripper.rb,
lib/sequel/adapters/jdbc/postgresql.rb,
lib/sequel/adapters/shared/firebird.rb,
lib/sequel/adapters/shared/informix.rb,
lib/sequel/adapters/shared/postgres.rb,
lib/sequel/adapters/shared/progress.rb,
lib/sequel/extensions/_model_pg_row.rb,
lib/sequel/extensions/_pretty_table.rb,
lib/sequel/extensions/filter_having.rb,
lib/sequel/extensions/pg_hstore_ops.rb,
lib/sequel/extensions/schema_dumper.rb,
lib/sequel/extensions/select_remove.rb,
lib/sequel/extensions/set_overrides.rb,
lib/sequel/plugins/accessed_columns.rb,
lib/sequel/plugins/after_initialize.rb,
lib/sequel/plugins/auto_validations.rb,
lib/sequel/plugins/column_conflicts.rb,
lib/sequel/plugins/instance_filters.rb,
lib/sequel/plugins/inverted_subsets.rb,
lib/sequel/plugins/typecast_on_load.rb,
lib/sequel/plugins/unlimited_update.rb,
lib/sequel/plugins/update_or_create.rb,
lib/sequel/adapters/jdbc/firebirdsql.rb,
lib/sequel/adapters/jdbc/sqlanywhere.rb,
lib/sequel/database/dataset_defaults.rb,
lib/sequel/database/schema_generator.rb,
lib/sequel/extensions/pg_loose_count.rb,
lib/sequel/extensions/query_literals.rb,
lib/sequel/extensions/schema_caching.rb,
lib/sequel/extensions/server_logging.rb,
lib/sequel/model/default_inflections.rb,
lib/sequel/plugins/before_after_save.rb,
lib/sequel/plugins/input_transformer.rb,
lib/sequel/plugins/many_through_many.rb,
lib/sequel/plugins/nested_attributes.rb,
lib/sequel/plugins/subset_conditions.rb,
lib/sequel/adapters/jdbc/jdbcprogress.rb,
lib/sequel/adapters/jdbc/transactions.rb,
lib/sequel/extensions/date_arithmetic.rb,
lib/sequel/extensions/freeze_datasets.rb,
lib/sequel/extensions/named_timezones.rb,
lib/sequel/extensions/split_array_nil.rb,
lib/sequel/plugins/blacklist_security.rb,
lib/sequel/plugins/def_dataset_method.rb,
lib/sequel/plugins/hook_class_methods.rb,
lib/sequel/plugins/identifier_columns.rb,
lib/sequel/plugins/optimistic_locking.rb,
lib/sequel/plugins/update_primary_key.rb,
lib/sequel/plugins/validation_helpers.rb,
lib/sequel/plugins/whitelist_security.rb,
lib/sequel/adapters/jdbc/informix-sqli.rb,
lib/sequel/adapters/shared/sqlanywhere.rb,
lib/sequel/adapters/utils/mysql_mysql2.rb,
lib/sequel/dataset/prepared_statements.rb,
lib/sequel/extensions/round_timestamps.rb,
lib/sequel/plugins/association_proxies.rb,
lib/sequel/plugins/pg_typecast_on_load.rb,
lib/sequel/plugins/prepared_statements.rb,
lib/sequel/plugins/skip_create_refresh.rb,
lib/sequel/plugins/validate_associated.rb,
lib/sequel/plugins/validation_contexts.rb,
lib/sequel/extensions/arbitrary_servers.rb,
lib/sequel/extensions/implicit_subquery.rb,
lib/sequel/plugins/dataset_associations.rb,
lib/sequel/plugins/singular_table_names.rb,
lib/sequel/extensions/looser_typecasting.rb,
lib/sequel/plugins/delay_add_association.rb,
lib/sequel/plugins/many_to_one_pk_lookup.rb,
lib/sequel/plugins/pg_array_associations.rb,
lib/sequel/extensions/identifier_mangling.rb,
lib/sequel/plugins/constraint_validations.rb,
lib/sequel/plugins/modification_detection.rb,
lib/sequel/plugins/tactical_eager_loading.rb,
lib/sequel/dataset/placeholder_literalizer.rb,
lib/sequel/extensions/auto_literal_strings.rb,
lib/sequel/extensions/connection_validator.rb,
lib/sequel/extensions/dataset_source_alias.rb,
lib/sequel/plugins/class_table_inheritance.rb,
lib/sequel/plugins/insert_returning_select.rb,
lib/sequel/adapters/utils/stored_procedures.rb,
lib/sequel/extensions/columns_introspection.rb,
lib/sequel/extensions/connection_expiration.rb,
lib/sequel/plugins/association_dependencies.rb,
lib/sequel/plugins/mssql_optimistic_locking.rb,
lib/sequel/plugins/prepared_statements_safe.rb,
lib/sequel/plugins/single_table_inheritance.rb,
lib/sequel/plugins/validation_class_methods.rb,
lib/sequel/extensions/constraint_validations.rb,
lib/sequel/extensions/thread_local_timezones.rb,
lib/sequel/plugins/association_autoreloading.rb,
lib/sequel/extensions/no_auto_literal_strings.rb,
lib/sequel/extensions/pg_static_cache_updater.rb,
lib/sequel/extensions/sequel_3_dataset_methods.rb,
lib/sequel/extensions/sequel_4_dataset_methods.rb,
lib/sequel/extensions/virtual_row_method_block.rb,
lib/sequel/plugins/prepared_statements_with_pk.rb,
lib/sequel/extensions/duplicate_columns_handler.rb,
lib/sequel/adapters/utils/unmodified_identifiers.rb,
lib/sequel/extensions/current_datetime_timestamp.rb,
lib/sequel/extensions/empty_array_consider_nulls.rb,
lib/sequel/adapters/utils/mysql_prepared_statements.rb,
lib/sequel/extensions/_model_constraint_validations.rb,
lib/sequel/plugins/prepared_statements_associations.rb,
lib/sequel/extensions/_deprecated_identifier_mangling.rb,
lib/sequel/extensions/mssql_emulate_lateral_with_apply.rb,
lib/sequel/plugins/serialization_modification_detection.rb,
lib/sequel/adapters/utils/emulate_offset_with_row_number.rb,
lib/sequel/adapters/utils/emulate_offset_with_reverse_and_count.rb

Overview

The duplicate_columns_handler extension allows you to customize handling of duplicate column names in your queries on a per-database or per-dataset level.

For example, you may want to raise an exception if you join 2 tables together which contains a column that will override another columns.

To use the extension, you need to load the extension into the database:

DB.extension :duplicate_columns_handler

A database option is introduced: :on_duplicate_columns. It accepts a Symbol or any object that responds to :call.

:on_duplicate_columns => :raise
:on_duplicate_columns => :warn
:on_duplicate_columns => :ignore
:on_duplicate_columns => proc { |columns| arbitrary_condition? ? :raise : :warn }

You may also configure duplicate columns handling for a specific dataset:

ds.on_duplicate_columns(:warn)
ds.on_duplicate_columns(:raise)
ds.on_duplicate_columns(:ignore)
ds.on_duplicate_columns { |columns| arbitrary_condition? ? :raise : :warn }
ds.on_duplicate_columns(proc { |columns| arbitrary_condition? ? :raise : :warn })

If :raise is specified, a Sequel::DuplicateColumnError is raised. If :warn is specified, you will receive a warning via ‘warn`. If a callable is specified, it will be called. If no on_duplicate_columns is specified, the default is :warn.

Related module: Sequel::DuplicateColumnsHandler

Defined Under Namespace

Modules: ADO, Access, Amalgalite, ArbitraryServers, ColumnsIntrospection, ConnectionExpiration, ConnectionValidator, ConstraintValidations, CoreRefinements, Cubrid, CurrentDateTimeTimestamp, DB2, DataObjects, DatabaseQuery, DatasetPagination, DatasetPrinter, DatasetQuery, DeprecatedIdentifierMangling, Deprecation, DuplicateColumnsHandler, EmptyArrayConsiderNulls, EmulateOffsetWithReverseAndCount, EmulateOffsetWithRowNumber, ErrorSQL, EvalInspect, FilterHaving, Firebird, GraphEach, HashAliases, IBMDB, IdentifierMangling, Inflections, Informix, JDBC, LooserTypecasting, MSSQL, Metaprogramming, Mock, MySQL, Mysql2, NamedTimezones, ODBC, Oracle, Plugins, Postgres, PrettyTable, Progress, QueryLiterals, S, SQL, SQLComments, SQLite, Schema, SchemaCaching, SchemaDumper, SelectRemove, Sequel3DatasetMethods, Sequel4DatasetMethods, ServerBlock, ServerLogging, SetOverrides, SqlAnywhere, Swift, SymbolAref, SymbolAs, ThreadLocalTimezones, ThreadedServerBlock, Timezones, TinyTDS, UnmodifiedIdentifiers, UnthreadedServerBlock Classes: ASTTransformer, BasicObject, ConnectionPool, Database, DatabaseError, Dataset, DuplicateColumnError, Error, HookFailed, IntegerMigrator, LiteralString, Migration, MigrationAlterTableReverser, MigrationDSL, MigrationReverser, Migrator, Model, NoMatchingRow, Qualifier, SQLTime, ShardedSingleConnectionPool, ShardedThreadedConnectionPool, SimpleMigration, SingleConnectionPool, ThreadedConnectionPool, TimestampMigrator, ToDot, Unbinder, ValidationFailed

Constant Summary collapse

VIRTUAL_ROW = 
new
OPTS =

Frozen hash used as the default options hash for most options.

{}.freeze
SPLIT_SYMBOL_CACHE = 
{}
COLUMN_REF_RE1 = 
/\A((?:(?!__).)+)__((?:(?!___).)+)___(.+)\z/.freeze
COLUMN_REF_RE2 = 
/\A((?:(?!___).)+)___(.+)\z/.freeze
COLUMN_REF_RE3 = 
/\A((?:(?!__).)+)__(.+)\z/.freeze
MAJOR =

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

4
MINOR =

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

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TINY =

The tiny version of Sequel. Usually 0, only bumped for bugfix releases that fix regressions from previous versions.

0
VERSION =

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

[MAJOR, MINOR, TINY].join('.').freeze
ADAPTER_MAP =

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

{}
SHARED_ADAPTER_MAP =

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.

{}
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.

[]
BeforeHookFailed =

Alias for HookFailed, kept for backwards compatibility

HookFailed
DEFAULT_INFLECTIONS_PROC =

Proc that is instance evaled to create the default inflections for both the model inflector and the inflector extension.

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

Constants included from SQL::Constants

SQL::Constants::CURRENT_DATE, SQL::Constants::CURRENT_TIME, SQL::Constants::CURRENT_TIMESTAMP, SQL::Constants::NOTNULL, SQL::Constants::NULL, SQL::Constants::SQLFALSE, SQL::Constants::SQLTRUE

Class Attribute Summary collapse

Attributes included from Timezones

#application_timezone, #database_timezone, #typecast_timezone

Attributes included from NamedTimezones

#tzinfo_disambiguator

Class Method Summary collapse

Methods included from SQL::Builders

as, asc, blob, case, cast, cast_numeric, cast_string, char_length, date_add, date_sub, deep_qualify, delay, desc, expr, extract, function, hstore, hstore_op, identifier, ilike, join, like, lit, negate, or, pg_array, pg_array_op, pg_inet_op, pg_json, pg_json_op, pg_jsonb, pg_jsonb_op, pg_range, pg_range_op, pg_row, pg_row_op, qualify, string_agg, subscript, trim, value_list

Methods included from SQL::OperatorBuilders

**, ~

Methods included from Timezones

application_to_database_timestamp, convert_output_timestamp, convert_timestamp, database_to_application_timestamp, default_timezone=, typecast_to_application_timestamp

Methods included from EvalInspect

eval_inspect

Class Attribute Details

.convert_two_digit_years ⇒ Object

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 37

def convert_two_digit_years
  @convert_two_digit_years
end

.datetime_class ⇒ Object

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).



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# File 'lib/sequel/core.rb', line 51

def datetime_class
  @datetime_class
end

.single_threaded ⇒ Object

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 60

def single_threaded
  @single_threaded
end

Class Method Details

.cache_anonymous_models ⇒ Object

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



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9
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# File 'lib/sequel/model.rb', line 7

def self.cache_anonymous_models
  Sequel::Deprecation.deprecate("Sequel.cache_anonymous_models", "Use Sequel::Model.cache_anonymous_models")
  Model.cache_anonymous_models
end

.cache_anonymous_models=(v) ⇒ Object

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



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# File 'lib/sequel/model.rb', line 13

def self.cache_anonymous_models=(v)
  Sequel::Deprecation.deprecate("Sequel.cache_anonymous_models=", "Use Sequel::Model.cache_anonymous_models=")
  Model.cache_anonymous_models = v
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 72

def self.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: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.



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

def self.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 128

def self.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

.core_extensions? ⇒ Boolean

This extension loads the core extensions.

Returns:

  • (Boolean) 


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# File 'lib/sequel/core.rb', line 121

def self.core_extensions?
  false
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. 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(:blank)
Sequel.extension(:core_extensions, :named_timezones)



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

def self.extension(*extensions)
  extensions.each{|e| Kernel.require "sequel/extensions/#{e}"}
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 instance methods work as well.



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# File 'lib/sequel/core.rb', line 161

def self.identifier_input_method=(value)
  # SEQUEL5: Remove
  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 instance methods work as well.



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# File 'lib/sequel/core.rb', line 178

def self.identifier_output_method=(value)
  # SEQUEL5: Remove
  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 6

def self.inflections
  yield Inflections if block_given?
  Inflections
end

.json_parser_error_class ⇒ Object

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 185

def self.json_parser_error_class
  JSON::ParserError
end

.migration(&block) ⇒ Object

The preferred method for writing Sequel migrations, using a DSL:

Sequel.migration do
  up do
    create_table(:artists) do
      primary_key :id
      String :name
    end
  end

  down do
    drop_table(:artists)
  end
end

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



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# File 'lib/sequel/extensions/migration.rb', line 289

def self.migration(&block)
  MigrationDSL.create(&block)
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 191

def self.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 197

def self.parse_json(json)
  JSON.parse(json, :create_additions=>false)
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 205

def self.quote_identifiers=(value)
  # SEQUEL5: Remove
  Database.quote_identifiers = value
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 213

def self.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

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.



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# File 'lib/sequel/core.rb', line 227

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

.split_symbol(sym) ⇒ Object

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.



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# File 'lib/sequel/core.rb', line 240

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})")
        end
        [$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})")
        end
        [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})")
        end
        [$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

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::Identifier#[].

# 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 304

def self.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 310

def self.split_symbols?
  @split_symbols
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 317

def self.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 329

def self.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 345

def self.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.



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# File 'lib/sequel/core.rb', line 359

def self.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 385

def self.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

.version ⇒ Object

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



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# File 'lib/sequel/version.rb', line 17

def self.version
  VERSION
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 409

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