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:



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# 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.



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

def lock
  @lock
end

#logger ⇒ Object (readonly)

Returns the value of attribute logger.



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# 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.



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

def owner
  @owner
end

#pool ⇒ Object

Returns the value of attribute pool.



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

def pool
  @pool
end

#visitor ⇒ Object (readonly)

Returns the value of attribute visitor.



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# 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:



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# 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) 


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

def self.database_exists?(config)
  raise NotImplementedError
end

.quoted_column_names ⇒ Object

:nodoc:



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# 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:



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# 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 



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# 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 



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# 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) 


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# 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.



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# 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) 


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# 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) 


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

def all_foreign_keys_valid?
  true
end

#async_enabled? ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# 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.



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# 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:



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# 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:



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# 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:



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# 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:



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# 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.



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# 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



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

def close
  pool.checkin self
end

#connection_class ⇒ Object

:nodoc:



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# 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



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

def create_enum(*) # :nodoc:
end

#database_version ⇒ Object

:nodoc:



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# 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) 


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# 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:



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# 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



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# 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.



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# 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.



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# 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.



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# 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



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# 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



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# 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.



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

def extensions
  []
end

#field_ordered_value(column, values) ⇒ Object

:nodoc:



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# 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



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

def get_advisory_lock(lock_id) # :nodoc:
end

#get_database_version ⇒ Object

:nodoc:



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# 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.



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# 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



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# 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:



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# 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:



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# 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) 


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# 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) 


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# 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:



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# 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) 


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# 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.



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# 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.



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# 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



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

def release_advisory_lock(lock_id) # :nodoc:
end

#replica? ⇒ Boolean

Returns:

  • (Boolean) 


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# 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) 


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# 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.



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# 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 (ie :writing) for the current connection. In a non-multi role application, `:writing` is returned.



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

def role
  @pool.role
end

#schema_cache ⇒ Object 



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

def schema_cache
  @pool.get_schema_cache(self)
end

#schema_cache=(cache) ⇒ Object 



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# 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:



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# 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.



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# 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



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# 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 (ie :default) for the current connection. In a non-sharded application, `:default` is returned.



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# 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)



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# 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) 


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

def supports_advisory_locks?
  false
end

#supports_bulk_alter? ⇒ Boolean

Returns:

  • (Boolean) 


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# 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) 


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# 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) 


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# 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) 


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# 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) 


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

def supports_common_table_expressions?
  false
end

#supports_concurrent_connections? ⇒ Boolean

Returns:

  • (Boolean) 


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# 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) 


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# 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) 


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# 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) 


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# 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) 


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# 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) 


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# 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) 


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# 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) 


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# 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) 


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# 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) 


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# 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) 


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# 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) 


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# 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) 


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# 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) 


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# 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) 


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# 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) 


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

def supports_json?
  false
end

#supports_lazy_transactions? ⇒ Boolean

Returns:

  • (Boolean) 


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# 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) 


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# 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) 


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# 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) 


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

def supports_partial_index?
  false
end

#supports_partitioned_indexes? ⇒ Boolean

Returns:

  • (Boolean) 


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# 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) 


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# 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) 


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# 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) 


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# 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) 


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# 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) 


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# 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.



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

def throw_away!
  pool.remove self
  disconnect!
end

#unprepared_statement ⇒ Object 



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# 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) 


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# 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) 


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# 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.



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

def verify!
  reconnect! unless active?
end

#with_instrumenter(instrumenter, &block) ⇒ Object

:nodoc:



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# 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