Class: ActiveRecord::ConnectionAdapters::AbstractAdapter

Inherits:
Object
  • Object
show all
Includes:
DatabaseLimits, DatabaseStatements, QueryCache, Quoting, Savepoints, SchemaStatements, ActiveSupport::Callbacks
Defined in:
lib/active_record/connection_adapters/abstract_adapter.rb

Overview

Active Record supports multiple database systems. AbstractAdapter and related classes form the abstraction layer which makes this possible. An AbstractAdapter represents a connection to a database, and provides an abstract interface for database-specific functionality such as establishing a connection, escaping values, building the right SQL fragments for :offset and :limit options, etc.

All the concrete database adapters follow the interface laid down in this class. ActiveRecord::Base.connection returns an AbstractAdapter object, which you can use.

Most of the methods in the adapter are useful during migrations. Most notably, the instance methods provided by SchemaStatements are very useful.

Defined Under Namespace

Classes: Version

Constant Summary collapse

ADAPTER_NAME = 
"Abstract"
SIMPLE_INT = 
/\A\d+\z/
COMMENT_REGEX = 
%r{(?:--.*\n)|/\*(?:[^*]|\*[^/])*\*/}m
TYPE_MAP = 
Type::TypeMap.new.tap { |m| initialize_type_map(m) }

Instance Attribute Summary collapse

Attributes included from QueryCache

#query_cache, #query_cache_enabled

Attributes included from DatabaseStatements

#transaction_manager

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Savepoints

#create_savepoint, #current_savepoint_name, #exec_rollback_to_savepoint, #release_savepoint

Methods included from QueryCache

#cache, #clear_query_cache, dirties_query_cache, #disable_query_cache!, #enable_query_cache!, included, #select_all, #uncached

Methods included from DatabaseLimits

#index_name_length, #max_identifier_length, #table_alias_length

Methods included from Quoting

#column_name_matcher, #column_name_with_order_matcher, #lookup_cast_type_from_column, #quote, #quote_bound_value, #quote_column_name, #quote_default_expression, #quote_string, #quote_table_name, #quote_table_name_for_assignment, #quoted_binary, #quoted_date, #quoted_false, #quoted_time, #quoted_true, #sanitize_as_sql_comment, #type_cast, #unquoted_false, #unquoted_true

Methods included from DatabaseStatements

#add_transaction_record, #begin_db_transaction, #begin_isolated_db_transaction, #cacheable_query, #commit_db_transaction, #default_sequence_name, #delete, #empty_insert_statement_value, #exec_delete, #exec_insert, #exec_insert_all, #exec_query, #exec_rollback_db_transaction, #exec_update, #execute, #explain, #high_precision_current_timestamp, #insert, #insert_fixture, #insert_fixtures_set, #mark_transaction_written_if_write, #query, #query_value, #query_values, #reset_sequence!, #reset_transaction, #rollback_db_transaction, #rollback_to_savepoint, #sanitize_limit, #select_all, #select_one, #select_rows, #select_value, #select_values, #to_sql, #transaction, #transaction_isolation_levels, #transaction_open?, #truncate, #truncate_tables, #update, #with_yaml_fallback, #write_query?

Methods included from SchemaStatements

#add_check_constraint, #add_column, #add_columns, #add_foreign_key, #add_index, #add_index_options, #add_reference, #add_timestamps, #assume_migrated_upto_version, #change_column, #change_column_comment, #change_column_default, #change_column_null, #change_table, #change_table_comment, #check_constraint_options, #check_constraints, #column_exists?, #columns, #columns_for_distinct, #create_join_table, #create_schema_dumper, #create_table, #data_source_exists?, #data_sources, #distinct_relation_for_primary_key, #drop_join_table, #drop_table, #dump_schema_information, #foreign_key_column_for, #foreign_key_exists?, #foreign_key_options, #foreign_keys, #index_algorithm, #index_exists?, #index_name, #index_name_exists?, #indexes, #internal_string_options_for_primary_key, #native_database_types, #options_include_default?, #primary_key, #quoted_columns_for_index, #remove_check_constraint, #remove_column, #remove_columns, #remove_foreign_key, #remove_index, #remove_reference, #remove_timestamps, #rename_column, #rename_index, #rename_table, #table_alias_for, #table_comment, #table_exists?, #table_options, #tables, #type_to_sql, #update_table_definition, #view_exists?, #views

Constructor Details

#initialize(connection, logger = nil, config = {}) ⇒ AbstractAdapter

:nodoc:



82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 82

def initialize(connection, logger = nil, config = {}) # :nodoc:
  super()

  @connection          = connection
  @owner               = nil
  @instrumenter        = ActiveSupport::Notifications.instrumenter
  @logger              = logger
  @config              = config
  @pool                = ActiveRecord::ConnectionAdapters::NullPool.new
  @idle_since          = Process.clock_gettime(Process::CLOCK_MONOTONIC)
  @visitor = arel_visitor
  @statements = build_statement_pool
  @lock = ActiveSupport::Concurrency::LoadInterlockAwareMonitor.new

  @prepared_statements = self.class.type_cast_config_to_boolean(
    config.fetch(:prepared_statements, true)
  )

  @advisory_locks_enabled = self.class.type_cast_config_to_boolean(
    config.fetch(:advisory_locks, true)
  )
end

Instance Attribute Details

#lock ⇒ Object (readonly)

Returns the value of attribute lock.



42
43
44
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 42

def lock
  @lock
end

#logger ⇒ Object (readonly)

Returns the value of attribute logger.



42
43
44
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 42

def logger
  @logger
end

#owner ⇒ Object (readonly) Also known as: in_use?

Returns the value of attribute owner.



42
43
44
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 42

def owner
  @owner
end

#pool ⇒ Object

Returns the value of attribute pool.



41
42
43
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 41

def pool
  @pool
end

#visitor ⇒ Object (readonly)

Returns the value of attribute visitor.



42
43
44
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 42

def visitor
  @visitor
end

Class Method Details

.build_read_query_regexp(*parts) ⇒ Object

:nodoc:



68
69
70
71
72
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 68

def self.build_read_query_regexp(*parts) # :nodoc:
  parts += DEFAULT_READ_QUERY
  parts = parts.map { |part| /#{part}/i }
  /\A(?:[(\s]|#{COMMENT_REGEX})*#{Regexp.union(*parts)}/
end

.database_exists?(config) ⇒ Boolean

Does the database for this adapter exist?

Returns:

  • (Boolean)

Raises:

  • (NotImplementedError) 


297
298
299
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 297

def self.database_exists?(config)
  raise NotImplementedError
end

.quoted_column_names ⇒ Object

:nodoc:



74
75
76
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 74

def self.quoted_column_names # :nodoc:
  @quoted_column_names ||= {}
end

.quoted_table_names ⇒ Object

:nodoc:



78
79
80
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 78

def self.quoted_table_names # :nodoc:
  @quoted_table_names ||= {}
end

.type_cast_config_to_boolean(config) ⇒ Object 



57
58
59
60
61
62
63
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 57

def self.type_cast_config_to_boolean(config)
  if config == "false"
    false
  else
    config
  end
end

.type_cast_config_to_integer(config) ⇒ Object 



47
48
49
50
51
52
53
54
55
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 47

def self.type_cast_config_to_integer(config)
  if config.is_a?(Integer)
    config
  elsif SIMPLE_INT.match?(config)
    config.to_i
  else
    config
  end
end

Instance Method Details

#active? ⇒ Boolean

Checks whether the connection to the database is still active. This includes checking whether the database is actually capable of responding, i.e. whether the connection isn’t stale.

Returns:

  • (Boolean) 


523
524
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 523

def active?
end

#adapter_name ⇒ Object

Returns the human-readable name of the adapter. Use mixed case - one can always use downcase if needed.



292
293
294
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 292

def adapter_name
  self.class::ADAPTER_NAME
end

#advisory_locks_enabled? ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


478
479
480
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 478

def advisory_locks_enabled? # :nodoc:
  supports_advisory_locks? && @advisory_locks_enabled
end

#all_foreign_keys_valid? ⇒ Boolean

Override to check all foreign key constraints in a database.

Returns:

  • (Boolean) 


514
515
516
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 514

def all_foreign_keys_valid?
  true
end

#async_enabled? ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


461
462
463
464
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 461

def async_enabled? # :nodoc:
  supports_concurrent_connections? &&
    !ActiveRecord.async_query_executor.nil? && !pool.async_executor.nil?
end

#build_insert_sql(insert) ⇒ Object

Called by ActiveRecord::InsertAll, Passed an instance of ActiveRecord::InsertAll::Builder, This method implements standard bulk inserts for all databases, but should be overridden by adapters to implement common features with non-standard syntax like handling duplicates or returning values.



638
639
640
641
642
643
644
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 638

def build_insert_sql(insert) # :nodoc:
  if insert.skip_duplicates? || insert.update_duplicates?
    raise NotImplementedError, "#{self.class} should define `build_insert_sql` to implement adapter-specific logic for handling duplicates during INSERT"
  end

  "INSERT #{insert.into} #{insert.values_list}"
end

#case_insensitive_comparison(attribute, value) ⇒ Object

:nodoc:



609
610
611
612
613
614
615
616
617
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 609

def case_insensitive_comparison(attribute, value) # :nodoc:
  column = column_for_attribute(attribute)

  if can_perform_case_insensitive_comparison_for?(column)
    attribute.lower.eq(attribute.relation.lower(value))
  else
    attribute.eq(value)
  end
end

#case_sensitive_comparison(attribute, value) ⇒ Object

:nodoc:



605
606
607
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 605

def case_sensitive_comparison(attribute, value) # :nodoc:
  attribute.eq(value)
end

#check_if_write_query(sql) ⇒ Object

:nodoc:



118
119
120
121
122
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 118

def check_if_write_query(sql) # :nodoc:
  if preventing_writes? && write_query?(sql)
    raise ActiveRecord::ReadOnlyError, "Write query attempted while in readonly mode: #{sql}"
  end
end

#check_version ⇒ Object

:nodoc:



653
654
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 653

def check_version # :nodoc:
end

#clear_cache! ⇒ Object

Clear any caching the database adapter may be doing.



574
575
576
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 574

def clear_cache!
  @lock.synchronize { @statements.clear } if @statements
end

#close ⇒ Object

Check the connection back in to the connection pool



625
626
627
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 625

def close
  pool.checkin self
end

#connection_class ⇒ Object

:nodoc:



223
224
225
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 223

def connection_class # :nodoc:
  @pool.connection_class
end

#create_enum ⇒ Object

This is meant to be implemented by the adapters that support custom enum types



475
476
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 475

def create_enum(*) # :nodoc:
end

#database_version ⇒ Object

:nodoc:



649
650
651
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 649

def database_version # :nodoc:
  schema_cache.database_version
end

#default_index_type?(index) ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


629
630
631
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 629

def default_index_type?(index) # :nodoc:
  index.using.nil?
end

#default_uniqueness_comparison(attribute, value) ⇒ Object

:nodoc:



601
602
603
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 601

def default_uniqueness_comparison(attribute, value) # :nodoc:
  attribute.eq(value)
end

#disable_extension(name) ⇒ Object

This is meant to be implemented by the adapters that support extensions



467
468
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 467

def disable_extension(name)
end

#disable_referential_integrity ⇒ Object

Override to turn off referential integrity while executing &block.



509
510
511
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 509

def disable_referential_integrity
  yield
end

#discard! ⇒ Object

Immediately forget this connection ever existed. Unlike disconnect!, this will not communicate with the server.

After calling this method, the behavior of all other methods becomes undefined. This is called internally just before a forked process gets rid of a connection that belonged to its parent.



547
548
549
550
551
552
553
554
555
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 547

def discard!
  # This should be overridden by concrete adapters.
  #
  # Prevent @connection's finalizer from touching the socket, or
  # otherwise communicating with its server, when it is collected.
  if schema_cache.connection == self
    schema_cache.connection = nil
  end
end

#disconnect! ⇒ Object

Disconnects from the database if already connected. Otherwise, this method does nothing.



536
537
538
539
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 536

def disconnect!
  clear_cache!
  reset_transaction
end

#enable_extension(name) ⇒ Object

This is meant to be implemented by the adapters that support extensions



471
472
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 471

def enable_extension(name)
end

#expire ⇒ Object

this method must only be called while holding connection pool’s mutex



249
250
251
252
253
254
255
256
257
258
259
260
261
262
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 249

def expire
  if in_use?
    if @owner != Thread.current
      raise ActiveRecordError, "Cannot expire connection, " \
        "it is owned by a different thread: #{@owner}. " \
        "Current thread: #{Thread.current}."
    end

    @idle_since = Process.clock_gettime(Process::CLOCK_MONOTONIC)
    @owner = nil
  else
    raise ActiveRecordError, "Cannot expire connection, it is not currently leased."
  end
end

#extensions ⇒ Object

A list of extensions, to be filled in by adapters that support them.



497
498
499
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 497

def extensions
  []
end

#field_ordered_value(column, values) ⇒ Object

:nodoc:



664
665
666
667
668
669
670
671
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 664

def field_ordered_value(column, values) # :nodoc:
  node = Arel::Nodes::Case.new(column)
  values.each.with_index(1) do |value, order|
    node.when(value).then(order)
  end

  Arel::Nodes::Ascending.new(node.else(values.length + 1))
end

#get_advisory_lock(lock_id) ⇒ Object

This is meant to be implemented by the adapters that support advisory locks

Return true if we got the lock, otherwise false



486
487
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 486

def get_advisory_lock(lock_id) # :nodoc:
end

#get_database_version ⇒ Object

:nodoc:



646
647
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 646

def get_database_version # :nodoc:
end

#index_algorithms ⇒ Object

A list of index algorithms, to be filled by adapters that support them.



502
503
504
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 502

def index_algorithms
  {}
end

#lease ⇒ Object

this method must only be called while holding connection pool’s mutex



208
209
210
211
212
213
214
215
216
217
218
219
220
221
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 208

def lease
  if in_use?
    msg = +"Cannot lease connection, "
    if @owner == Thread.current
      msg << "it is already leased by the current thread."
    else
      msg << "it is already in use by a different thread: #{@owner}. " \
             "Current thread: #{Thread.current}."
    end
    raise ActiveRecordError, msg
  end

  @owner = Thread.current
end

#migration_context ⇒ Object

:nodoc:



153
154
155
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 153

def migration_context # :nodoc:
  MigrationContext.new(migrations_paths, schema_migration)
end

#migrations_paths ⇒ Object

:nodoc:



149
150
151
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 149

def migrations_paths # :nodoc:
  @config[:migrations_paths] || Migrator.migrations_paths
end

#prefetch_primary_key?(table_name = nil) ⇒ Boolean

Should primary key values be selected from their corresponding sequence before the insert statement? If true, next_sequence_value is called before each insert to set the record’s primary key.

Returns:

  • (Boolean) 


324
325
326
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 324

def prefetch_primary_key?(table_name = nil)
  false
end

#prepared_statements? ⇒ Boolean Also known as: prepared_statements

Returns:

  • (Boolean) 


175
176
177
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 175

def prepared_statements?
  @prepared_statements && !prepared_statements_disabled_cache.include?(object_id)
end

#prepared_statements_disabled_cache ⇒ Object

:nodoc:



180
181
182
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 180

def prepared_statements_disabled_cache # :nodoc:
  ActiveSupport::IsolatedExecutionState[:active_record_prepared_statements_disabled_cache] ||= Set.new
end

#preventing_writes? ⇒ Boolean

Determines whether writes are currently being prevented.

Returns true if the connection is a replica.

If the application is using legacy handling, returns true if connection_handler.prevent_writes is set.

If the application is using the new connection handling will return true based on current_preventing_writes.

Returns:

  • (Boolean) 


141
142
143
144
145
146
147
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 141

def preventing_writes?
  return true if replica?
  return ActiveRecord::Base.connection_handler.prevent_writes if ActiveRecord.legacy_connection_handling
  return false if connection_class.nil?

  connection_class.current_preventing_writes
end

#raw_connection ⇒ Object

Provides access to the underlying database driver for this adapter. For example, this method returns a Mysql2::Client object in case of Mysql2Adapter, and a PG::Connection object in case of PostgreSQLAdapter.

This is useful for when you need to call a proprietary method such as PostgreSQL’s lo_* methods.



596
597
598
599
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 596

def raw_connection
  disable_lazy_transactions!
  @connection
end

#reconnect! ⇒ Object

Disconnects from the database if already connected, and establishes a new connection with the database. Implementors should call super if they override the default implementation.



529
530
531
532
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 529

def reconnect!
  clear_cache!
  reset_transaction
end

#release_advisory_lock(lock_id) ⇒ Object

This is meant to be implemented by the adapters that support advisory locks.

Return true if we released the lock, otherwise false



493
494
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 493

def release_advisory_lock(lock_id) # :nodoc:
end

#replica? ⇒ Boolean

Returns:

  • (Boolean) 


124
125
126
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 124

def replica?
  @config[:replica] || false
end

#requires_reloading? ⇒ Boolean

Returns true if its required to reload the connection between requests for development mode.

Returns:

  • (Boolean) 


579
580
581
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 579

def requires_reloading?
  false
end

#reset! ⇒ Object

Reset the state of this connection, directing the DBMS to clear transactions and other connection-related server-side state. Usually a database-dependent operation.

The default implementation does nothing; the implementation should be overridden by concrete adapters.



563
564
565
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 563

def reset!
  # this should be overridden by concrete adapters
end

#role ⇒ Object

The role (e.g. :writing) for the current connection. In a non-multi role application, :writing is returned.



229
230
231
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 229

def role
  @pool.role
end

#schema_cache ⇒ Object 



239
240
241
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 239

def schema_cache
  @pool.get_schema_cache(self)
end

#schema_cache=(cache) ⇒ Object 



243
244
245
246
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 243

def schema_cache=(cache)
  cache.connection = self
  @pool.set_schema_cache(cache)
end

#schema_migration ⇒ Object

:nodoc:



157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 157

def schema_migration # :nodoc:
  @schema_migration ||= begin
                          conn = self
                          spec_name = conn.pool.pool_config.connection_specification_name

                          return ActiveRecord::SchemaMigration if spec_name == "ActiveRecord::Base"

                          schema_migration_name = "#{spec_name}::SchemaMigration"

                          Class.new(ActiveRecord::SchemaMigration) do
                            define_singleton_method(:name) { schema_migration_name }
                            define_singleton_method(:to_s) { schema_migration_name }

                            self.connection_specification_name = spec_name
                          end
                        end
end

#schema_version ⇒ Object

Returns the version identifier of the schema currently available in the database. This is generally equal to the number of the highest- numbered migration that has been executed, or 0 if no schema information is present / the database is empty.



660
661
662
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 660

def schema_version
  migration_context.current_version
end

#seconds_idle ⇒ Object

Seconds since this connection was returned to the pool



278
279
280
281
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 278

def seconds_idle # :nodoc:
  return 0 if in_use?
  Process.clock_gettime(Process::CLOCK_MONOTONIC) - @idle_since
end

#shard ⇒ Object

The shard (e.g. :default) for the current connection. In a non-sharded application, :default is returned.



235
236
237
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 235

def shard
  @pool.shard
end

#steal! ⇒ Object

this method must only be called while holding connection pool’s mutex (and a desire for segfaults)



265
266
267
268
269
270
271
272
273
274
275
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 265

def steal! # :nodoc:
  if in_use?
    if @owner != Thread.current
      pool.send :remove_connection_from_thread_cache, self, @owner

      @owner = Thread.current
    end
  else
    raise ActiveRecordError, "Cannot steal connection, it is not currently leased."
  end
end

#supports_advisory_locks? ⇒ Boolean

Does this adapter support application-enforced advisory locking?

Returns:

  • (Boolean) 


317
318
319
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 317

def supports_advisory_locks?
  false
end

#supports_bulk_alter? ⇒ Boolean

Returns:

  • (Boolean) 


307
308
309
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 307

def supports_bulk_alter?
  false
end

#supports_check_constraints? ⇒ Boolean

Does this adapter support creating check constraints?

Returns:

  • (Boolean) 


384
385
386
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 384

def supports_check_constraints?
  false
end

#supports_comments? ⇒ Boolean

Does this adapter support metadata comments on database objects (tables, columns, indexes)?

Returns:

  • (Boolean) 


409
410
411
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 409

def supports_comments?
  false
end

#supports_comments_in_create? ⇒ Boolean

Can comments for tables, columns, and indexes be specified in create/alter table statements?

Returns:

  • (Boolean) 


414
415
416
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 414

def supports_comments_in_create?
  false
end

#supports_common_table_expressions? ⇒ Boolean

Returns:

  • (Boolean) 


433
434
435
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 433

def supports_common_table_expressions?
  false
end

#supports_concurrent_connections? ⇒ Boolean

Returns:

  • (Boolean) 


457
458
459
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 457

def supports_concurrent_connections?
  true
end

#supports_datetime_with_precision? ⇒ Boolean

Does this adapter support datetime with precision?

Returns:

  • (Boolean) 


399
400
401
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 399

def supports_datetime_with_precision?
  false
end

#supports_ddl_transactions? ⇒ Boolean

Does this adapter support DDL rollbacks in transactions? That is, would CREATE TABLE or ALTER TABLE get rolled back by a transaction?

Returns:

  • (Boolean) 


303
304
305
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 303

def supports_ddl_transactions?
  false
end

#supports_deferrable_constraints? ⇒ Boolean

Does this adapter support creating deferrable constraints?

Returns:

  • (Boolean) 


379
380
381
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 379

def supports_deferrable_constraints?
  false
end

#supports_explain? ⇒ Boolean

Does this adapter support explain?

Returns:

  • (Boolean) 


348
349
350
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 348

def supports_explain?
  false
end

#supports_expression_index? ⇒ Boolean

Does this adapter support expression indices?

Returns:

  • (Boolean) 


343
344
345
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 343

def supports_expression_index?
  false
end

#supports_extensions? ⇒ Boolean

Does this adapter support database extensions?

Returns:

  • (Boolean) 


358
359
360
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 358

def supports_extensions?
  false
end

#supports_foreign_keys? ⇒ Boolean

Does this adapter support creating foreign key constraints?

Returns:

  • (Boolean) 


369
370
371
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 369

def supports_foreign_keys?
  false
end

#supports_foreign_tables? ⇒ Boolean

Does this adapter support foreign/external tables?

Returns:

  • (Boolean) 


424
425
426
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 424

def supports_foreign_tables?
  false
end

#supports_index_sort_order? ⇒ Boolean

Does this adapter support index sort order?

Returns:

  • (Boolean) 


333
334
335
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 333

def supports_index_sort_order?
  false
end

#supports_indexes_in_create? ⇒ Boolean

Does this adapter support creating indexes in the same statement as creating the table?

Returns:

  • (Boolean) 


364
365
366
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 364

def supports_indexes_in_create?
  false
end

#supports_insert_conflict_target? ⇒ Boolean

Returns:

  • (Boolean) 


453
454
455
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 453

def supports_insert_conflict_target?
  false
end

#supports_insert_on_duplicate_skip? ⇒ Boolean

Returns:

  • (Boolean) 


445
446
447
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 445

def supports_insert_on_duplicate_skip?
  false
end

#supports_insert_on_duplicate_update? ⇒ Boolean

Returns:

  • (Boolean) 


449
450
451
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 449

def supports_insert_on_duplicate_update?
  false
end

#supports_insert_returning? ⇒ Boolean

Returns:

  • (Boolean) 


441
442
443
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 441

def supports_insert_returning?
  false
end

#supports_json? ⇒ Boolean

Does this adapter support json data type?

Returns:

  • (Boolean) 


404
405
406
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 404

def supports_json?
  false
end

#supports_lazy_transactions? ⇒ Boolean

Returns:

  • (Boolean) 


437
438
439
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 437

def supports_lazy_transactions?
  false
end

#supports_materialized_views? ⇒ Boolean

Does this adapter support materialized views?

Returns:

  • (Boolean) 


394
395
396
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 394

def supports_materialized_views?
  false
end

#supports_optimizer_hints? ⇒ Boolean

Does this adapter support optimizer hints?

Returns:

  • (Boolean) 


429
430
431
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 429

def supports_optimizer_hints?
  false
end

#supports_partial_index? ⇒ Boolean

Does this adapter support partial indices?

Returns:

  • (Boolean) 


338
339
340
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 338

def supports_partial_index?
  false
end

#supports_partitioned_indexes? ⇒ Boolean

Returns:

  • (Boolean) 


328
329
330
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 328

def supports_partitioned_indexes?
  false
end

#supports_savepoints? ⇒ Boolean

Does this adapter support savepoints?

Returns:

  • (Boolean) 


312
313
314
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 312

def supports_savepoints?
  false
end

#supports_transaction_isolation? ⇒ Boolean

Does this adapter support setting the isolation level for a transaction?

Returns:

  • (Boolean) 


353
354
355
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 353

def supports_transaction_isolation?
  false
end

#supports_validate_constraints? ⇒ Boolean

Does this adapter support creating invalid constraints?

Returns:

  • (Boolean) 


374
375
376
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 374

def supports_validate_constraints?
  false
end

#supports_views? ⇒ Boolean

Does this adapter support views?

Returns:

  • (Boolean) 


389
390
391
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 389

def supports_views?
  false
end

#supports_virtual_columns? ⇒ Boolean

Does this adapter support virtual columns?

Returns:

  • (Boolean) 


419
420
421
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 419

def supports_virtual_columns?
  false
end

#throw_away! ⇒ Object

Removes the connection from the pool and disconnect it.



568
569
570
571
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 568

def throw_away!
  pool.remove self
  disconnect!
end

#unprepared_statement ⇒ Object 



283
284
285
286
287
288
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 283

def unprepared_statement
  cache = prepared_statements_disabled_cache.add?(object_id) if @prepared_statements
  yield
ensure
  cache&.delete(object_id)
end

#use_metadata_table? ⇒ Boolean

Returns:

  • (Boolean) 


128
129
130
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 128

def use_metadata_table?
  @config.fetch(:use_metadata_table, true)
end

#valid_type?(type) ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


203
204
205
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 203

def valid_type?(type) # :nodoc:
  !native_database_types[type].nil?
end

#verify! ⇒ Object

Checks whether the connection to the database is still active (i.e. not stale). This is done under the hood by calling #active?. If the connection is no longer active, then this method will reconnect to the database.



586
587
588
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 586

def verify!
  reconnect! unless active?
end

#with_instrumenter(instrumenter, &block) ⇒ Object

:nodoc:



108
109
110
111
112
113
114
115
116
 
# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 108

def with_instrumenter(instrumenter, &block) # :nodoc:
  Thread.handle_interrupt(EXCEPTION_NEVER) do
    previous_instrumenter = @instrumenter
    @instrumenter = instrumenter
    Thread.handle_interrupt(EXCEPTION_IMMEDIATE, &block)
  ensure
    @instrumenter = previous_instrumenter
  end
end