Class: ActiveRecord::ConnectionAdapters::AbstractAdapter
- Inherits:
-
Object
- Object
- ActiveRecord::ConnectionAdapters::AbstractAdapter
- Includes:
- ColumnDumper, DatabaseLimits, DatabaseStatements, QueryCache, Quoting, SchemaStatements, ActiveSupport::Callbacks, MonitorMixin
- Defined in:
- lib/active_record/connection_adapters/abstract_adapter.rb,
lib/active_record/connection_adapters/abstract/schema_creation.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 SchemaStatement are very useful.
Direct Known Subclasses
Defined Under Namespace
Classes: BindCollector, SQLString, SchemaCreation
Constant Summary collapse
- ADAPTER_NAME =
'Abstract'.freeze
- SIMPLE_INT =
/\A\d+\z/
Instance Attribute Summary collapse
-
#logger ⇒ Object
readonly
Returns the value of attribute logger.
-
#owner ⇒ Object
(also: #in_use?)
readonly
Returns the value of attribute owner.
-
#pool ⇒ Object
Returns the value of attribute pool.
-
#prepared_statements ⇒ Object
readonly
Returns the value of attribute prepared_statements.
-
#schema_cache ⇒ Object
Returns the value of attribute schema_cache.
-
#visitor ⇒ Object
Returns the value of attribute visitor.
Attributes included from QueryCache
#query_cache, #query_cache_enabled
Attributes included from DatabaseStatements
Class Method Summary collapse
Instance Method Summary collapse
-
#active? ⇒ Boolean
Checks whether the connection to the database is still active.
-
#adapter_name ⇒ Object
Returns the human-readable name of the adapter.
- #case_insensitive_comparison(table, attribute, column, value) ⇒ Object
- #case_sensitive_comparison(table, attribute, column, value) ⇒ Object
- #case_sensitive_modifier(node, table_attribute) ⇒ Object
-
#clear_cache! ⇒ Object
Clear any caching the database adapter may be doing, for example clearing the prepared statement cache.
-
#close ⇒ Object
Check the connection back in to the connection pool.
- #collector ⇒ Object
-
#column_name_for_operation(operation, node) ⇒ Object
:nodoc:.
- #create_savepoint(name = nil) ⇒ Object
- #current_savepoint_name ⇒ Object
-
#disable_extension(name) ⇒ Object
This is meant to be implemented by the adapters that support extensions.
-
#disable_referential_integrity ⇒ Object
Override to turn off referential integrity while executing
&block
. -
#disconnect! ⇒ Object
Disconnects from the database if already connected.
-
#enable_extension(name) ⇒ Object
This is meant to be implemented by the adapters that support extensions.
- #expire ⇒ Object
-
#extensions ⇒ Object
A list of extensions, to be filled in by adapters that support them.
-
#index_algorithms ⇒ Object
A list of index algorithms, to be filled by adapters that support them.
-
#initialize(connection, logger = nil, pool = nil) ⇒ AbstractAdapter
constructor
:nodoc:.
- #lease ⇒ Object
-
#lookup_cast_type(sql_type) ⇒ Object
:nodoc:.
- #new_column(name, default, cast_type, sql_type = nil, null = true) ⇒ Object
-
#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.
-
#raw_connection ⇒ Object
Provides access to the underlying database driver for this adapter.
-
#reconnect! ⇒ Object
Disconnects from the database if already connected, and establishes a new connection with the database.
- #release_savepoint(name = nil) ⇒ Object
-
#requires_reloading? ⇒ Boolean
Returns true if its required to reload the connection between requests for development mode.
-
#reset! ⇒ Object
Reset the state of this connection, directing the DBMS to clear transactions and other connection-related server-side state.
- #schema_creation ⇒ Object
-
#substitute_at(column, _unused = 0) ⇒ Object
Returns a bind substitution value given a bind
column
NOTE: The column param is currently being used by the sqlserver-adapter. - #supports_bulk_alter? ⇒ Boolean
-
#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?.
-
#supports_explain? ⇒ Boolean
Does this adapter support explain?.
-
#supports_extensions? ⇒ Boolean
Does this adapter support database extensions?.
-
#supports_foreign_keys? ⇒ Boolean
Does this adapter support creating foreign key constraints?.
-
#supports_index_sort_order? ⇒ Boolean
Does this adapter support index sort order?.
-
#supports_indexes_in_create? ⇒ Boolean
Does this adapter support creating indexes in the same statement as creating the table?.
-
#supports_migrations? ⇒ Boolean
Does this adapter support migrations?.
-
#supports_partial_index? ⇒ Boolean
Does this adapter support partial indices?.
-
#supports_primary_key? ⇒ Boolean
Can this adapter determine the primary key for tables not attached to an Active Record class, such as join tables?.
-
#supports_savepoints? ⇒ Boolean
Does this adapter support savepoints?.
-
#supports_transaction_isolation? ⇒ Boolean
Does this adapter support setting the isolation level for a transaction?.
-
#supports_views? ⇒ Boolean
Does this adapter support views?.
-
#type_map ⇒ Object
:nodoc:.
- #unprepared_statement ⇒ Object
- #valid_type?(type) ⇒ Boolean
-
#verify!(*ignored) ⇒ Object
Checks whether the connection to the database is still active (i.e. not stale).
Methods included from ColumnDumper
#column_spec, #migration_keys, #prepare_column_options
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
#allowed_index_name_length, #column_name_length, #columns_per_multicolumn_index, #columns_per_table, #in_clause_length, #index_name_length, #indexes_per_table, #joins_per_query, #sql_query_length, #table_alias_length, #table_name_length
Methods included from Quoting
#quote, #quote_column_name, #quote_string, #quote_table_name, #quote_table_name_for_assignment, #quoted_date, #quoted_false, #quoted_true, #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_query, #exec_rollback_db_transaction, #exec_rollback_to_savepoint, #exec_update, #execute, #insert, #insert_fixture, #join_to_delete, #join_to_update, #reset_sequence!, #reset_transaction, #rollback_db_transaction, #rollback_to_savepoint, #sanitize_limit, #select_all, #select_one, #select_rows, #select_value, #select_values, #supports_statement_cache?, #to_sql, #transaction, #transaction_isolation_levels, #transaction_open?, #truncate, #update
Methods included from SchemaStatements
#add_column, #add_foreign_key, #add_index, #add_index_options, #add_reference, #add_timestamps, #assume_migrated_upto_version, #change_column, #change_column_default, #change_column_null, #change_table, #column_exists?, #columns, #columns_for_distinct, #create_join_table, #create_table, #drop_join_table, #drop_table, #dump_schema_information, #foreign_key_column_for, #foreign_keys, #index_exists?, #index_name, #index_name_exists?, #initialize_schema_migrations_table, #native_database_types, #remove_column, #remove_columns, #remove_foreign_key, #remove_index, #remove_index!, #remove_reference, #remove_timestamps, #rename_column, #rename_index, #rename_table, #table_alias_for, #table_exists?, #type_to_sql, #update_table_definition
Methods included from TimestampDefaultDeprecation
#emit_warning_if_null_unspecified
Constructor Details
#initialize(connection, logger = nil, pool = nil) ⇒ AbstractAdapter
:nodoc:
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 101 def initialize(connection, logger = nil, pool = nil) #:nodoc: super() @connection = connection @owner = nil @instrumenter = ActiveSupport::Notifications.instrumenter @logger = logger @pool = pool @schema_cache = SchemaCache.new self @visitor = nil @prepared_statements = false end |
Instance Attribute Details
#logger ⇒ Object (readonly)
Returns the value of attribute logger.
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 80 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 80 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 79 def pool @pool end |
#prepared_statements ⇒ Object (readonly)
Returns the value of attribute prepared_statements.
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 99 def prepared_statements @prepared_statements end |
#schema_cache ⇒ Object
Returns the value of attribute schema_cache.
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 80 def schema_cache @schema_cache end |
#visitor ⇒ Object
Returns the value of attribute visitor.
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 79 def visitor @visitor end |
Class Method Details
.type_cast_config_to_boolean(config) ⇒ Object
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 91 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 83 def self.type_cast_config_to_integer(config) if config =~ SIMPLE_INT 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.
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 284 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 168 def adapter_name self.class::ADAPTER_NAME end |
#case_insensitive_comparison(table, attribute, column, value) ⇒ Object
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 357 def case_insensitive_comparison(table, attribute, column, value) table[attribute].lower.eq(table.lower(value)) end |
#case_sensitive_comparison(table, attribute, column, value) ⇒ Object
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 351 def case_sensitive_comparison(table, attribute, column, value) table_attr = table[attribute] value = case_sensitive_modifier(value, table_attr) unless value.nil? table_attr.eq(value) end |
#case_sensitive_modifier(node, table_attribute) ⇒ Object
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 347 def case_sensitive_modifier(node, table_attribute) node end |
#clear_cache! ⇒ Object
Clear any caching the database adapter may be doing, for example clearing the prepared statement cache. This is database specific.
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 315 def clear_cache! # this should be overridden by concrete adapters 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 366 def close pool.checkin self end |
#collector ⇒ Object
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 126 def collector if prepared_statements SQLString.new else BindCollector.new end end |
#column_name_for_operation(operation, node) ⇒ Object
:nodoc:
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 384 def column_name_for_operation(operation, node) # :nodoc: visitor.accept(node, collector).value end |
#create_savepoint(name = nil) ⇒ Object
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 341 def create_savepoint(name = nil) end |
#current_savepoint_name ⇒ Object
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 361 def current_savepoint_name current_transaction.savepoint_name 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 247 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 275 def disable_referential_integrity yield 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 297 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 251 def enable_extension(name) end |
#expire ⇒ Object
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 155 def expire @owner = nil 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 255 def extensions [] 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 260 def index_algorithms {} end |
#lease ⇒ Object
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 142 def lease synchronize do unless in_use? @owner = Thread.current end end end |
#lookup_cast_type(sql_type) ⇒ Object
:nodoc:
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 380 def lookup_cast_type(sql_type) # :nodoc: type_map.lookup(sql_type) end |
#new_column(name, default, cast_type, sql_type = nil, null = true) ⇒ Object
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 376 def new_column(name, default, cast_type, sql_type = nil, null = true) Column.new(name, default, cast_type, sql_type, null) 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.
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 201 def prefetch_primary_key?(table_name = nil) false end |
#raw_connection ⇒ Object
Provides access to the underlying database driver for this adapter. For example, this method returns a Mysql object in case of MysqlAdapter, and a PGconn 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 337 def raw_connection @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 290 def reconnect! clear_cache! reset_transaction end |
#release_savepoint(name = nil) ⇒ Object
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 344 def release_savepoint(name = nil) end |
#requires_reloading? ⇒ Boolean
Returns true if its required to reload the connection between requests for development mode.
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 320 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 308 def reset! # this should be overridden by concrete adapters end |
#schema_creation ⇒ Object
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 138 def schema_creation SchemaCreation.new self end |
#substitute_at(column, _unused = 0) ⇒ Object
Returns a bind substitution value given a bind column
NOTE: The column param is currently being used by the sqlserver-adapter
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 268 def substitute_at(column, _unused = 0) Arel::Nodes::BindParam.new end |
#supports_bulk_alter? ⇒ Boolean
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 189 def supports_bulk_alter? 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?
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 185 def supports_ddl_transactions? false end |
#supports_explain? ⇒ Boolean
Does this adapter support explain?
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 216 def supports_explain? false end |
#supports_extensions? ⇒ Boolean
Does this adapter support database extensions?
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 226 def supports_extensions? false end |
#supports_foreign_keys? ⇒ Boolean
Does this adapter support creating foreign key constraints?
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 237 def supports_foreign_keys? false end |
#supports_index_sort_order? ⇒ Boolean
Does this adapter support index sort order?
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 206 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?
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 232 def supports_indexes_in_create? false end |
#supports_migrations? ⇒ Boolean
Does this adapter support migrations?
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 173 def supports_migrations? false end |
#supports_partial_index? ⇒ Boolean
Does this adapter support partial indices?
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 211 def supports_partial_index? false end |
#supports_primary_key? ⇒ Boolean
Can this adapter determine the primary key for tables not attached to an Active Record class, such as join tables?
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 179 def supports_primary_key? false end |
#supports_savepoints? ⇒ Boolean
Does this adapter support savepoints?
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 194 def supports_savepoints? false end |
#supports_transaction_isolation? ⇒ Boolean
Does this adapter support setting the isolation level for a transaction?
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 221 def supports_transaction_isolation? false end |
#supports_views? ⇒ Boolean
Does this adapter support views?
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 242 def supports_views? false end |
#type_map ⇒ Object
:nodoc:
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 370 def type_map # :nodoc: @type_map ||= Type::TypeMap.new.tap do |mapping| initialize_type_map(mapping) end end |
#unprepared_statement ⇒ Object
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 159 def unprepared_statement old_prepared_statements, @prepared_statements = @prepared_statements, false yield ensure @prepared_statements = old_prepared_statements end |
#valid_type?(type) ⇒ Boolean
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# File 'lib/active_record/connection_adapters/abstract_adapter.rb', line 134 def valid_type?(type) true end |
#verify!(*ignored) ⇒ 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 327 def verify!(*ignored) reconnect! unless active? end |