Module: ActiveRecord::ConnectionAdapters::DatabaseStatements
Relationships & Source Files | |
Extension / Inclusion / Inheritance Descendants | |
Included In:
| |
Defined in: | activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb |
Constant Summary
-
DEFAULT_INSERT_VALUE =
private
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 600Arel.sql("DEFAULT").freeze
-
HIGH_PRECISION_CURRENT_TIMESTAMP =
private
Internal use only
This is a safe default, even if not high precision on all databases
Arel.sql("CURRENT_TIMESTAMP", retryable: true).freeze
Instance Attribute Summary
- #begin_transaction readonly
- #commit_transaction readonly
- #current_transaction readonly
- #dirty_current_transaction readonly
- #materialize_transactions readonly
- #open_transactions readonly
- #rollback_transaction readonly
- #transaction_open? ⇒ Boolean readonly
- #within_new_transaction readonly
- #transaction_manager readonly Internal use only
Instance Method Summary
-
#add_transaction_record(record, ensure_finalize = true)
Register a record with the current transaction so that its after_commit and after_rollback callbacks can be called.
-
#begin_db_transaction
Begins the transaction (and turns off auto-committing).
-
#begin_isolated_db_transaction(isolation)
Begins the transaction with the isolation level set.
-
#commit_db_transaction
Commits the transaction (and turns on auto-committing).
-
#create(arel, name = nil, pk = nil, id_value = nil, sequence_name = nil, binds = [], returning: nil)
Alias for #insert.
- #default_sequence_name(table, column)
-
#delete(arel, name = nil, binds = [])
Executes the delete statement and returns the number of rows affected.
- #disable_lazy_transactions!
- #empty_insert_statement_value(primary_key = nil)
- #enable_lazy_transactions!
-
#exec_delete(sql, name = nil, binds = [])
Executes delete
sql
statement in the context of this connection usingbinds
as the bind substitutes. -
#exec_insert(sql, name = nil, binds = [], pk = nil, sequence_name = nil, returning: nil)
Executes insert
sql
statement in the context of this connection usingbinds
as the bind substitutes. -
#exec_query(sql, name = "SQL", binds = [], prepare: false)
Executes
sql
statement in the context of this connection usingbinds
as the bind substitutes. -
#exec_update(sql, name = nil, binds = [])
Executes update
sql
statement in the context of this connection usingbinds
as the bind substitutes. -
#execute(sql, name = nil, allow_retry: false)
Executes the SQL statement in the context of this connection and returns the raw result from the connection adapter.
-
#high_precision_current_timestamp
Returns an
::Arel
SQL literal for the CURRENT_TIMESTAMP for usage with arbitrary precision date/time columns. - #initialize
-
#insert(arel, name = nil, pk = nil, id_value = nil, sequence_name = nil, binds = [], returning: nil)
(also: #create)
Executes an INSERT query and returns the new record’s ID.
-
#insert_fixture(fixture, table_name)
Inserts the given fixture into the table.
- #insert_fixtures_set(fixture_set, tables_to_delete = [])
-
#reset_isolation_level
Hook point called after an isolated DB transaction is committed or rolled back.
-
#reset_sequence!(table, column, sequence = nil)
Set the sequence to the max value of the table’s column.
- #restart_db_transaction
-
#rollback_db_transaction
Rolls back the transaction (and turns on auto-committing).
- #rollback_to_savepoint(name = nil)
-
#sanitize_limit(limit)
Sanitizes the given LIMIT parameter in order to prevent SQL injection.
-
#select_all(arel, name = nil, binds = [], preparable: nil, async: false, allow_retry: false)
Returns an
::ActiveRecord::Result
instance. -
#select_one(arel, name = nil, binds = [], async: false)
Returns a record hash with the column names as keys and column values as values.
-
#select_rows(arel, name = nil, binds = [], async: false)
Returns an array of arrays containing the field values.
-
#select_value(arel, name = nil, binds = [], async: false)
Returns a single value from a record.
-
#select_values(arel, name = nil, binds = [])
Returns an array of the values of the first column in a select:
-
#to_sql(arel_or_sql_string, binds = [])
Converts an arel AST to SQL.
-
#transaction(requires_new: nil, isolation: nil, joinable: true, &block)
Runs the given block in a database transaction, and returns the result of the block.
- #transaction_isolation_levels
-
#truncate(table_name, name = nil)
Executes the truncate statement.
-
#update(arel, name = nil, binds = [])
Executes the update statement and returns the number of rows affected.
-
#write_query?(sql) ⇒ Boolean
Determines whether the SQL statement is a write query.
- #affected_rows(raw_result) private
- #arel_from_relation(relation) private
- #build_fixture_sql(fixtures, table_name) private
- #build_fixture_statements(fixture_set) private
- #build_truncate_statement(table_name) private
- #build_truncate_statements(table_names) private
-
#cast_result(raw_result)
private
Receive a native adapter result object and returns an
::ActiveRecord::Result
object. - #combine_multi_statements(total_sql) private
- #default_insert_value(column) private
- #execute_batch(statements, name = nil, **kwargs) private
- #extract_table_ref_from_insert_sql(sql) private
-
#internal_execute(sql, name = "SQL", binds = [], prepare: false, async: false, allow_retry: false, materialize_transactions: true, &block)
private
Same as #internal_exec_query, but yields a native adapter result.
- #last_inserted_id(result) private
- #perform_query(raw_connection, sql, binds, type_casted_binds, prepare:, notification_payload:, batch:) private
- #preprocess_query(sql) private
-
#raw_execute(sql, name = nil, binds = [], prepare: false, async: false, allow_retry: false, materialize_transactions: true, batch: false)
private
Lowest level way to execute a query.
- #returning_column_values(result) private
-
#select(sql, name = nil, binds = [], prepare: false, async: false, allow_retry: false)
private
Returns an
::ActiveRecord::Result
instance. - #single_value_from_rows(rows) private
- #begin_deferred_transaction(isolation_level = nil) Internal use only
-
#cacheable_query(klass, arel)
Internal use only
This is used in the
::ActiveRecord::StatementCache
object. - #exec_insert_all(sql, name) Internal use only
- #exec_restart_db_transaction Internal use only
- #exec_rollback_db_transaction Internal use only
- #explain(arel, binds = [], options = []) Internal use only
-
#internal_exec_query
Internal use only
Execute a query and returns an
::ActiveRecord::Result
- #mark_transaction_written_if_write(sql) Internal use only
- #query Internal use only
- #query_value Internal use only
- #query_values Internal use only
-
#raw_exec_query
Internal use only
Same as raw_execute but returns an
::ActiveRecord::Result
object. - #reset_transaction(restore: false) Internal use only
- #truncate_tables(*table_names) Internal use only
-
#with_yaml_fallback(value)
Internal use only
::ActiveRecord::Fixture
value is quoted by::Arel
, however scalar values are not quotable. - #sql_for_insert(sql, pk, binds, returning) private Internal use only
- #to_sql_and_binds(arel_or_sql_string, binds = [], preparable = nil, allow_retry = false) private Internal use only
Instance Attribute Details
#begin_transaction (readonly)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 367
delegate :within_new_transaction, :open_transactions, :current_transaction, :begin_transaction, :commit_transaction, :rollback_transaction, :materialize_transactions, :disable_lazy_transactions!, :enable_lazy_transactions!, :dirty_current_transaction, to: :transaction_manager
#commit_transaction (readonly)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 367
delegate :within_new_transaction, :open_transactions, :current_transaction, :begin_transaction, :commit_transaction, :rollback_transaction, :materialize_transactions, :disable_lazy_transactions!, :enable_lazy_transactions!, :dirty_current_transaction, to: :transaction_manager
#current_transaction (readonly)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 367
delegate :within_new_transaction, :open_transactions, :current_transaction, :begin_transaction, :commit_transaction, :rollback_transaction, :materialize_transactions, :disable_lazy_transactions!, :enable_lazy_transactions!, :dirty_current_transaction, to: :transaction_manager
#dirty_current_transaction (readonly)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 367
delegate :within_new_transaction, :open_transactions, :current_transaction, :begin_transaction, :commit_transaction, :rollback_transaction, :materialize_transactions, :disable_lazy_transactions!, :enable_lazy_transactions!, :dirty_current_transaction, to: :transaction_manager
#materialize_transactions (readonly)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 367
delegate :within_new_transaction, :open_transactions, :current_transaction, :begin_transaction, :commit_transaction, :rollback_transaction, :materialize_transactions, :disable_lazy_transactions!, :enable_lazy_transactions!, :dirty_current_transaction, to: :transaction_manager
#open_transactions (readonly)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 367
delegate :within_new_transaction, :open_transactions, :current_transaction, :begin_transaction, :commit_transaction, :rollback_transaction, :materialize_transactions, :disable_lazy_transactions!, :enable_lazy_transactions!, :dirty_current_transaction, to: :transaction_manager
#rollback_transaction (readonly)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 367
delegate :within_new_transaction, :open_transactions, :current_transaction, :begin_transaction, :commit_transaction, :rollback_transaction, :materialize_transactions, :disable_lazy_transactions!, :enable_lazy_transactions!, :dirty_current_transaction, to: :transaction_manager
#transaction_manager (readonly)
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 365
attr_reader :transaction_manager # :nodoc:
#transaction_open? ⇒ Boolean
(readonly)
[ GitHub ]
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 379
def transaction_open? current_transaction.open? end
#within_new_transaction (readonly)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 367
delegate :within_new_transaction, :open_transactions, :current_transaction, :begin_transaction, :commit_transaction, :rollback_transaction, :materialize_transactions, :disable_lazy_transactions!, :enable_lazy_transactions!, :dirty_current_transaction, to: :transaction_manager
Instance Method Details
#add_transaction_record(record, ensure_finalize = true)
Register a record with the current transaction so that its after_commit and after_rollback callbacks can be called.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 405
def add_transaction_record(record, ensure_finalize = true) current_transaction.add_record(record, ensure_finalize) end
#affected_rows(raw_result) (private)
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 570
def affected_rows(raw_result) raise NotImplementedError end
#arel_from_relation(relation) (private)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 732
def arel_from_relation(relation) if relation.is_a?(Relation) relation.arel else relation end end
#begin_db_transaction
Begins the transaction (and turns off auto-committing).
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 410
def begin_db_transaction() end
#begin_deferred_transaction(isolation_level = nil)
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 412
def begin_deferred_transaction(isolation_level = nil) # :nodoc: if isolation_level begin_isolated_db_transaction(isolation_level) else begin_db_transaction end end
#begin_isolated_db_transaction(isolation)
Begins the transaction with the isolation level set. Raises an error by default; adapters that support setting the isolation level should implement this method.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 432
def begin_isolated_db_transaction(isolation) raise ActiveRecord::TransactionIsolationError, "adapter does not support setting transaction isolation" end
#build_fixture_sql(fixtures, table_name) (private)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 607
def build_fixture_sql(fixtures, table_name) columns = schema_cache.columns_hash(table_name).reject { |_, column| supports_virtual_columns? && column.virtual? } values_list = fixtures.map do |fixture| fixture = fixture.stringify_keys unknown_columns = fixture.keys - columns.keys if unknown_columns.any? raise Fixture::FixtureError, %(table "#{table_name}" has no columns named #{unknown_columns.map(&:inspect).join(', ')}.) end columns.map do |name, column| if fixture.key?(name) type = lookup_cast_type_from_column(column) with_yaml_fallback(type.serialize(fixture[name])) else default_insert_value(column) end end end table = Arel::Table.new(table_name) manager = Arel::InsertManager.new(table) if values_list.size == 1 values = values_list.shift new_values = [] columns.each_key.with_index { |column, i| unless values[i].equal?(DEFAULT_INSERT_VALUE) new_values << values[i] manager.columns << table[column] end } values_list << new_values else columns.each_key { |column| manager.columns << table[column] } end manager.values = manager.create_values_list(values_list) visitor.compile(manager.ast) end
#build_fixture_statements(fixture_set) (private)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 649
def build_fixture_statements(fixture_set) fixture_set.filter_map do |table_name, fixtures| next if fixtures.empty? build_fixture_sql(fixtures, table_name) end end
#build_truncate_statement(table_name) (private)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 656
def build_truncate_statement(table_name) "TRUNCATE TABLE #{quote_table_name(table_name)}" end
#build_truncate_statements(table_names) (private)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 660
def build_truncate_statements(table_names) table_names.map do |table_name| build_truncate_statement(table_name) end end
#cacheable_query(klass, arel)
This is used in the ::ActiveRecord::StatementCache
object. It returns an object that can be used to query the database repeatedly.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 56
def cacheable_query(klass, arel) # :nodoc: if prepared_statements sql, binds = visitor.compile(arel.ast, collector) query = klass.query(sql) else collector = klass.partial_query_collector parts, binds = visitor.compile(arel.ast, collector) query = klass.partial_query(parts) end [query, binds] end
#cast_result(raw_result) (private)
Receive a native adapter result object and returns an ::ActiveRecord::Result
object.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 566
def cast_result(raw_result) raise NotImplementedError end
#combine_multi_statements(total_sql) (private)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 666
def combine_multi_statements(total_sql) total_sql.join(";\n") end
#commit_db_transaction
Commits the transaction (and turns on auto-committing).
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 446
def commit_db_transaction() end
#create(arel, name = nil, pk = nil, id_value = nil, sequence_name = nil, binds = [], returning: nil)
Alias for #insert.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 203
alias create insert
#default_insert_value(column) (private)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 603
def default_insert_value(column) DEFAULT_INSERT_VALUE end
#default_sequence_name(table, column)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 468
def default_sequence_name(table, column) nil end
#delete(arel, name = nil, binds = [])
Executes the delete statement and returns the number of rows affected.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 212
def delete(arel, name = nil, binds = []) sql, binds = to_sql_and_binds(arel, binds) exec_delete(sql, name, binds) end
#disable_lazy_transactions!
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 367
delegate :within_new_transaction, :open_transactions, :current_transaction, :begin_transaction, :commit_transaction, :rollback_transaction, :materialize_transactions, :disable_lazy_transactions!, :enable_lazy_transactions!, :dirty_current_transaction, to: :transaction_manager
#empty_insert_statement_value(primary_key = nil)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 498
def empty_insert_statement_value(primary_key = nil) "DEFAULT VALUES" end
#enable_lazy_transactions!
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 367
delegate :within_new_transaction, :open_transactions, :current_transaction, :begin_transaction, :commit_transaction, :rollback_transaction, :materialize_transactions, :disable_lazy_transactions!, :enable_lazy_transactions!, :dirty_current_transaction, to: :transaction_manager
#exec_delete(sql, name = nil, binds = [])
Executes delete sql
statement in the context of this connection using binds
as the bind substitutes. name
is logged along with the executed sql
statement.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 165
def exec_delete(sql, name = nil, binds = []) affected_rows(internal_execute(sql, name, binds)) end
#exec_insert(sql, name = nil, binds = [], pk = nil, sequence_name = nil, returning: nil)
Executes insert sql
statement in the context of this connection using binds
as the bind substitutes. name
is logged along with the executed sql
statement. Some adapters support the returning
keyword argument which allows to control the result of the query: nil
is the default value and maintains default behavior. If an array of column names is passed - the result will contain values of the specified columns from the inserted row.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 157
def exec_insert(sql, name = nil, binds = [], pk = nil, sequence_name = nil, returning: nil) sql, binds = sql_for_insert(sql, pk, binds, returning) internal_exec_query(sql, name, binds) end
#exec_insert_all(sql, name)
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 176
def exec_insert_all(sql, name) # :nodoc: internal_exec_query(sql, name) end
#exec_query(sql, name = "SQL", binds = [], prepare: false)
Executes sql
statement in the context of this connection using binds
as the bind substitutes. name
is logged along with the executed sql
statement.
Note: the query is assumed to have side effects and the query cache will be cleared. If the query is read-only, consider using #select_all instead.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 147
def exec_query(sql, name = "SQL", binds = [], prepare: false) internal_exec_query(sql, name, binds, prepare: prepare) end
#exec_restart_db_transaction
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 462
def exec_restart_db_transaction() end # :nodoc:
#exec_rollback_db_transaction
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 456
def exec_rollback_db_transaction() end # :nodoc:
#exec_update(sql, name = nil, binds = [])
Executes update sql
statement in the context of this connection using binds
as the bind substitutes. name
is logged along with the executed sql
statement.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 172
def exec_update(sql, name = nil, binds = []) affected_rows(internal_execute(sql, name, binds)) end
#execute(sql, name = nil, allow_retry: false)
Executes the SQL statement in the context of this connection and returns the raw result from the connection adapter.
Setting allow_retry
to true causes the db to reconnect and retry executing the SQL statement in case of a connection-related exception. This option should only be enabled for known idempotent queries.
Note: the query is assumed to have side effects and the query cache will be cleared. If the query is read-only, consider using #select_all instead.
Note: depending on your database connector, the result returned by this method may be manually memory managed. Consider using #exec_query wrapper instead.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 136
def execute(sql, name = nil, allow_retry: false) internal_execute(sql, name, allow_retry: allow_retry) end
#execute_batch(statements, name = nil, **kwargs) (private)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 594
def execute_batch(statements, name = nil, **kwargs) statements.each do |statement| raw_execute(statement, name, **kwargs) end end
#explain(arel, binds = [], options = [])
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 180
def explain(arel, binds = [], = []) # :nodoc: raise NotImplementedError end
#extract_table_ref_from_insert_sql(sql) (private)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 740
def extract_table_ref_from_insert_sql(sql) if sql =~ /into\s("[A-Za-z0-9_."\[\]\s]"|[A-Za-z0-9_."\[\]])\s*/im $1.delete('"').strip end end
#high_precision_current_timestamp
Returns an ::Arel
SQL literal for the CURRENT_TIMESTAMP for usage with arbitrary precision date/time columns.
Adapters supporting datetime with precision should override this to provide as much precision as is available.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 536
def HIGH_PRECISION_CURRENT_TIMESTAMP end
#initialize
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 6
def initialize super reset_transaction end
#insert(arel, name = nil, pk = nil, id_value = nil, sequence_name = nil, binds = [], returning: nil) Also known as: #create
Executes an INSERT query and returns the new record’s ID
id_value
will be returned unless the value is nil
, in which case the database will attempt to calculate the last inserted id and return that value.
If the next id was calculated in advance (as in Oracle), it should be passed in as id_value
. Some adapters support the returning
keyword argument which allows defining the return value of the method: nil
is the default value and maintains default behavior. If an array of column names is passed - an array of is returned from the method representing values of the specified columns from the inserted row.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 195
def insert(arel, name = nil, pk = nil, id_value = nil, sequence_name = nil, binds = [], returning: nil) sql, binds = to_sql_and_binds(arel, binds) value = exec_insert(sql, name, binds, pk, sequence_name, returning: returning) return returning_column_values(value) unless returning.nil? id_value || last_inserted_id(value) end
#insert_fixture(fixture, table_name)
Inserts the given fixture into the table. Overridden in adapters that require something beyond a simple insert (e.g. Oracle). Most of adapters should implement #insert_fixtures_set that leverages bulk SQL insert. We keep this method to provide fallback for databases like SQLite that do not support bulk inserts.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 482
def insert_fixture(fixture, table_name) execute(build_fixture_sql(Array.wrap(fixture), table_name), "Fixture Insert") end
#insert_fixtures_set(fixture_set, tables_to_delete = [])
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 486
def insert_fixtures_set(fixture_set, tables_to_delete = []) fixture_inserts = build_fixture_statements(fixture_set) table_deletes = tables_to_delete.map { |table| "DELETE FROM #{quote_table_name(table)}" } statements = table_deletes + fixture_inserts transaction(requires_new: true) do disable_referential_integrity do execute_batch(statements, "Fixtures Load") end end end
#internal_exec_query
Execute a query and returns an ::ActiveRecord::Result
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 546
def internal_exec_query(...) # :nodoc: cast_result(internal_execute(...)) end
#internal_execute(sql, name = "SQL", binds = [], prepare: false, async: false, allow_retry: false, materialize_transactions: true, &block) (private)
Same as #internal_exec_query, but yields a native adapter result
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 589
def internal_execute(sql, name = "SQL", binds = [], prepare: false, async: false, allow_retry: false, materialize_transactions: true, &block) sql = preprocess_query(sql) raw_execute(sql, name, binds, prepare: prepare, async: async, allow_retry: allow_retry, materialize_transactions: materialize_transactions, &block) end
#last_inserted_id(result) (private)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 719
def last_inserted_id(result) single_value_from_rows(result.rows) end
#mark_transaction_written_if_write(sql)
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 372
def mark_transaction_written_if_write(sql) # :nodoc: transaction = current_transaction if transaction.open? transaction.written ||= write_query?(sql) end end
#perform_query(raw_connection, sql, binds, type_casted_binds, prepare:, notification_payload:, batch:) (private)
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 561
def perform_query(raw_connection, sql, binds, type_casted_binds, prepare:, notification_payload:, batch:) raise NotImplementedError end
#preprocess_query(sql) (private)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 574
def preprocess_query(sql) check_if_write_query(sql) mark_transaction_written_if_write(sql) # We call tranformers after the write checks so we don't add extra parsing work. # This means we assume no transformer whille change a read for a write # but it would be insane to do such a thing. ActiveRecord.query_transformers.each do |transformer| sql = transformer.call(sql, self) end sql end
#query
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 113
def query(...) # :nodoc: internal_exec_query(...).rows end
#query_value
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 105
def query_value(...) # :nodoc: single_value_from_rows(query(...)) end
#query_values
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 109
def query_values(...) # :nodoc: query(...).map(&:first) end
#raw_exec_query
Same as raw_execute but returns an ::ActiveRecord::Result
object.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 541
def raw_exec_query(...) # :nodoc: cast_result(raw_execute(...)) end
#raw_execute(sql, name = nil, binds = [], prepare: false, async: false, allow_retry: false, materialize_transactions: true, batch: false) (private)
Lowest level way to execute a query. Doesn’t check for illegal writes, doesn’t annotate queries, yields a native result object.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 552
def raw_execute(sql, name = nil, binds = [], prepare: false, async: false, allow_retry: false, materialize_transactions: true, batch: false) type_casted_binds = type_casted_binds(binds) log(sql, name, binds, type_casted_binds, async: async) do |notification_payload| with_raw_connection(allow_retry: allow_retry, materialize_transactions: materialize_transactions) do |conn| perform_query(conn, sql, binds, type_casted_binds, prepare: prepare, notification_payload: notification_payload, batch: batch) end end end
#reset_isolation_level
Hook point called after an isolated DB transaction is committed or rolled back. Most adapters don’t need to implement anything because the isolation level is set on a per transaction basis. But some databases like SQLite set it on a per connection level and need to explicitly reset it after commit or rollback.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 442
def reset_isolation_level end
#reset_sequence!(table, column, sequence = nil)
Set the sequence to the max value of the table’s column.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 473
def reset_sequence!(table, column, sequence = nil) # Do nothing by default. Implement for PostgreSQL, Oracle, ... end
#reset_transaction(restore: false)
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 383
def reset_transaction(restore: false) # :nodoc: # Store the existing transaction state to the side old_state = @transaction_manager if restore && @transaction_manager&.restorable? @transaction_manager = ConnectionAdapters::TransactionManager.new(self) if block_given? # Reconfigure the connection without any transaction state in the way result = yield # Now the connection's fully established, we can swap back if old_state @transaction_manager = old_state @transaction_manager.restore_transactions end result end end
#restart_db_transaction
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 458
def restart_db_transaction exec_restart_db_transaction end
#returning_column_values(result) (private)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 723
def returning_column_values(result) [last_inserted_id(result)] end
#rollback_db_transaction
Rolls back the transaction (and turns on auto-committing). Must be done if the transaction block raises an exception or returns false.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 450
def rollback_db_transaction exec_rollback_db_transaction rescue ActiveRecord::ConnectionNotEstablished, ActiveRecord::ConnectionFailed # Connection's gone; that counts as a rollback end
#rollback_to_savepoint(name = nil)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 464
def rollback_to_savepoint(name = nil) exec_rollback_to_savepoint(name) end
#sanitize_limit(limit)
Sanitizes the given LIMIT parameter in order to prevent SQL injection.
The limit
may be anything that can evaluate to a string via #to_s
. It should look like an integer, or an ::Arel
SQL literal.
Returns Integer and ::Arel::Nodes::SqlLiteral
limits as is.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 508
def sanitize_limit(limit) if limit.is_a?(Integer) || limit.is_a?(Arel::Nodes::SqlLiteral) limit else Integer(limit) end end
#select(sql, name = nil, binds = [], prepare: false, async: false, allow_retry: false) (private)
Returns an ::ActiveRecord::Result
instance.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 671
def select(sql, name = nil, binds = [], prepare: false, async: false, allow_retry: false) if async && async_enabled? if current_transaction.joinable? raise AsynchronousQueryInsideTransactionError, "Asynchronous queries are not allowed inside transactions" end # We make sure to run query transformers on the original thread sql = preprocess_query(sql) future_result = async.new( pool, sql, name, binds, prepare: prepare, ) if supports_concurrent_connections? && !current_transaction.joinable? future_result.schedule!(ActiveRecord::Base.asynchronous_queries_session) else future_result.execute!(self) end future_result else result = internal_exec_query(sql, name, binds, prepare: prepare, allow_retry: allow_retry) if async FutureResult.wrap(result) else result end end end
#select_all(arel, name = nil, binds = [], preparable: nil, async: false, allow_retry: false)
Returns an ::ActiveRecord::Result
instance.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 69
def select_all(arel, name = nil, binds = [], preparable: nil, async: false, allow_retry: false) arel = arel_from_relation(arel) sql, binds, preparable, allow_retry = to_sql_and_binds(arel, binds, preparable, allow_retry) select(sql, name, binds, prepare: prepared_statements && preparable, async: async && FutureResult::SelectAll, allow_retry: allow_retry ) rescue ::RangeError ActiveRecord::Result.empty(async: async) end
#select_one(arel, name = nil, binds = [], async: false)
Returns a record hash with the column names as keys and column values as values.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 84
def select_one(arel, name = nil, binds = [], async: false) select_all(arel, name, binds, async: async).then(&:first) end
#select_rows(arel, name = nil, binds = [], async: false)
Returns an array of arrays containing the field values. Order is the same as that returned by columns
.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 101
def select_rows(arel, name = nil, binds = [], async: false) select_all(arel, name, binds, async: async).then(&:rows) end
#select_value(arel, name = nil, binds = [], async: false)
Returns a single value from a record
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 89
def select_value(arel, name = nil, binds = [], async: false) select_rows(arel, name, binds, async: async).then { |rows| single_value_from_rows(rows) } end
#select_values(arel, name = nil, binds = [])
Returns an array of the values of the first column in a select:
select_values("SELECT id FROM companies LIMIT 3") => [1,2,3]
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 95
def select_values(arel, name = nil, binds = []) select_rows(arel, name, binds).map(&:first) end
#single_value_from_rows(rows) (private)
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 727
def single_value_from_rows(rows) row = rows.first row && row.first end
#sql_for_insert(sql, pk, binds, returning) (private)
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 702
def sql_for_insert(sql, pk, binds, returning) # :nodoc: if supports_insert_returning? if pk.nil? # Extract the table from the insert sql. Yuck. table_ref = extract_table_ref_from_insert_sql(sql) pk = primary_key(table_ref) if table_ref end returning_columns = returning || Array(pk) returning_columns_statement = returning_columns.map { |c| quote_column_name(c) }.join(", ") sql = "#{sql} RETURNING #{returning_columns_statement}" if returning_columns.any? end [sql, binds] end
#to_sql(arel_or_sql_string, binds = [])
Converts an arel AST to SQL
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 12
def to_sql(arel_or_sql_string, binds = []) sql, _ = to_sql_and_binds(arel_or_sql_string, binds) sql end
#to_sql_and_binds(arel_or_sql_string, binds = [], preparable = nil, allow_retry = false) (private)
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 17
def to_sql_and_binds(arel_or_sql_string, binds = [], preparable = nil, allow_retry = false) # :nodoc: # Arel::TreeManager -> Arel::Node if arel_or_sql_string.respond_to?(:ast) arel_or_sql_string = arel_or_sql_string.ast end if Arel.arel_node?(arel_or_sql_string) && !(String === arel_or_sql_string) unless binds.empty? raise "Passing bind parameters with an arel AST is forbidden. " \ "The values must be stored on the AST directly" end collector = collector() collector.retryable = true if prepared_statements collector.preparable = true sql, binds = visitor.compile(arel_or_sql_string, collector) if binds.length > bind_params_length unprepared_statement do return to_sql_and_binds(arel_or_sql_string) end end preparable = collector.preparable else sql = visitor.compile(arel_or_sql_string, collector) end allow_retry = collector.retryable [sql.freeze, binds, preparable, allow_retry] else arel_or_sql_string = arel_or_sql_string.dup.freeze unless arel_or_sql_string.frozen? [arel_or_sql_string, binds, preparable, allow_retry] end end
#transaction(requires_new: nil, isolation: nil, joinable: true, &block)
Runs the given block in a database transaction, and returns the result of the block.
Transaction callbacks
#transaction
yields an ::ActiveRecord::Transaction
object on which it is possible to register callback:
ActiveRecord::Base.transaction do |transaction|
transaction.before_commit { puts "before commit!" }
transaction.after_commit { puts "after commit!" }
transaction.after_rollback { puts "after rollback!" }
end
Nested transactions support
#transaction
calls can be nested. By default, this makes all database statements in the nested transaction block become part of the parent transaction. For example, the following behavior may be surprising:
ActiveRecord::Base.transaction do
Post.create(title: 'first')
ActiveRecord::Base.transaction do
Post.create(title: 'second')
raise ActiveRecord::Rollback
end
end
This creates both “first” and “second” posts. Reason is the ::ActiveRecord::Rollback
exception in the nested block does not issue a ROLLBACK. Since these exceptions are captured in transaction blocks, the parent block does not see it and the real transaction is committed.
Most databases don’t support true nested transactions. At the time of writing, the only database that supports true nested transactions that we’re aware of, is MS-SQL.
In order to get around this problem, #transaction
will emulate the effect of nested transactions, by using savepoints: dev.mysql.com/doc/refman/en/savepoint.html.
It is safe to call this method if a database transaction is already open, i.e. if #transaction
is called within another #transaction
block. In case of a nested call, #transaction
will behave as follows:
-
The block will be run without doing anything. All database statements that happen within the block are effectively appended to the already open database transaction.
-
However, if
:requires_new
is set, the block will be wrapped in a database savepoint acting as a sub-transaction.
In order to get a ROLLBACK for the nested transaction you may ask for a real sub-transaction by passing requires_new: true
. If anything goes wrong, the database rolls back to the beginning of the sub-transaction without rolling back the parent transaction. If we add it to the previous example:
ActiveRecord::Base.transaction do
Post.create(title: 'first')
ActiveRecord::Base.transaction(requires_new: true) do
Post.create(title: 'second')
raise ActiveRecord::Rollback
end
end
only post with title “first” is created.
See ::ActiveRecord::Transactions
to learn more.
Caveats
MySQL
doesn’t support DDL transactions. If you perform a DDL operation, then any created savepoints will be automatically released. For example, if you’ve created a savepoint, then you execute a CREATE TABLE statement, then the savepoint that was created will be automatically released.
This means that, on MySQL
, you shouldn’t execute DDL operations inside a #transaction
call that you know might create a savepoint. Otherwise, #transaction
will raise exceptions when it tries to release the already-automatically-released savepoints:
Model.lease_connection.transaction do # BEGIN
Model.lease_connection.transaction(requires_new: true) do # CREATE SAVEPOINT active_record_1
Model.lease_connection.create_table(...)
# active_record_1 now automatically released
end # RELEASE SAVEPOINT active_record_1 <--- BOOM! database error!
end
Transaction isolation
If your database supports setting the isolation level for a transaction, you can set it like so:
Post.transaction(isolation: :serializable) do
# ...
end
Valid isolation levels are:
-
:read_uncommitted
-
:read_committed
-
:repeatable_read
-
:serializable
You should consult the documentation for your database to understand the semantics of these different levels:
An ::ActiveRecord::TransactionIsolationError
will be raised if:
-
The adapter does not support setting the isolation level
-
You are joining an existing open transaction
-
You are creating a nested (savepoint) transaction
The mysql2, trilogy, and postgresql adapters support setting the transaction isolation level.
:args: (requires_new: nil, isolation: nil, &block)
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 352
def transaction(requires_new: nil, isolation: nil, joinable: true, &block) if !requires_new && current_transaction.joinable? if isolation raise ActiveRecord::TransactionIsolationError, "cannot set isolation when joining a transaction" end yield current_transaction.user_transaction else within_new_transaction(isolation: isolation, joinable: joinable, &block) end rescue ActiveRecord::Rollback # rollbacks are silently swallowed end
#transaction_isolation_levels
[ GitHub ]# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 420
def transaction_isolation_levels { read_uncommitted: "READ UNCOMMITTED", read_committed: "READ COMMITTED", repeatable_read: "REPEATABLE READ", serializable: "SERIALIZABLE" } end
#truncate(table_name, name = nil)
Executes the truncate statement.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 218
def truncate(table_name, name = nil) execute(build_truncate_statement(table_name), name) end
#truncate_tables(*table_names)
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 222
def truncate_tables(*table_names) # :nodoc: table_names -= [pool.schema_migration.table_name, pool. .table_name] return if table_names.empty? disable_referential_integrity do statements = build_truncate_statements(table_names) execute_batch(statements, "Truncate Tables") end end
#update(arel, name = nil, binds = [])
Executes the update statement and returns the number of rows affected.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 206
def update(arel, name = nil, binds = []) sql, binds = to_sql_and_binds(arel, binds) exec_update(sql, name, binds) end
#with_yaml_fallback(value)
::ActiveRecord::Fixture
value is quoted by ::Arel
, however scalar values are not quotable. In this case we want to convert the column value to YAML.
#write_query?(sql) ⇒ Boolean
Determines whether the SQL statement is a write query.
# File 'activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb', line 118
def write_query?(sql) raise NotImplementedError end