require 'benchmark' require 'date' require 'bigdecimal' require 'bigdecimal/util' # TODO: Autoload these files require 'active_record/connection_adapters/abstract/schema_definitions' require 'active_record/connection_adapters/abstract/schema_statements' require 'active_record/connection_adapters/abstract/database_statements' require 'active_record/connection_adapters/abstract/quoting' require 'active_record/connection_adapters/abstract/connection_pool' require 'active_record/connection_adapters/abstract/connection_specification' require 'active_record/connection_adapters/abstract/query_cache' module ActiveRecord module ConnectionAdapters # :nodoc: # ActiveRecord 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. class AbstractAdapter include Quoting, DatabaseStatements, SchemaStatements include QueryCache include ActiveSupport::Callbacks define_callbacks :checkout, :checkin @@row_even = true def initialize(connection, logger = nil) #:nodoc: @connection, @logger = connection, logger @runtime = 0 @last_verification = 0 @query_cache_enabled = false end # Returns the human-readable name of the adapter. Use mixed case - one # can always use downcase if needed. def adapter_name 'Abstract' end # Does this adapter support migrations? Backend specific, as the # abstract adapter always returns +false+. def supports_migrations? false end # Does this adapter support using DISTINCT within COUNT? This is +true+ # for all adapters except sqlite. def supports_count_distinct? true end # Does this adapter support DDL rollbacks in transactions? That is, would # CREATE TABLE or ALTER TABLE get rolled back by a transaction? PostgreSQL, # SQL Server, and others support this. MySQL and others do not. def supports_ddl_transactions? false end # Does this adapter support savepoints? PostgreSQL and MySQL do, SQLite # does not. def supports_savepoints? false end # 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. # This is false for all adapters but Firebird. def prefetch_primary_key?(table_name = nil) false end def reset_runtime #:nodoc: rt, @runtime = @runtime, 0 rt end # QUOTING ================================================== # Override to return the quoted table name. Defaults to column quoting. def quote_table_name(name) quote_column_name(name) end # REFERENTIAL INTEGRITY ==================================== # Override to turn off referential integrity while executing &block. def disable_referential_integrity(&block) yield end # CONNECTION MANAGEMENT ==================================== # 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. def active? @active != false end # Disconnects from the database if already connected, and establishes a # new connection with the database. def reconnect! @active = true end # Disconnects from the database if already connected. Otherwise, this # method does nothing. def disconnect! @active = false end # 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. def reset! # this should be overridden by concrete adapters end # Returns true if its safe to reload the connection between requests for development mode. def requires_reloading? true end # 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. def verify!(*ignored) reconnect! unless active? end # 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. def raw_connection @connection end def open_transactions @open_transactions ||= 0 end def increment_open_transactions @open_transactions ||= 0 @open_transactions += 1 end def decrement_open_transactions @open_transactions -= 1 end def transaction_joinable=(joinable) @transaction_joinable = joinable end def create_savepoint end def rollback_to_savepoint end def release_savepoint end def current_savepoint_name "active_record_#{open_transactions}" end def log_info(sql, name, ms) if @logger && @logger.debug? name = '%s (%.1fms)' % [name || 'SQL', ms] @logger.debug(format_log_entry(name, sql.squeeze(' '))) end end protected def log(sql, name) if block_given? result = nil ms = Benchmark.ms { result = yield } @runtime += ms log_info(sql, name, ms) result else log_info(sql, name, 0) nil end rescue Exception => e # Log message and raise exception. # Set last_verification to 0, so that connection gets verified # upon reentering the request loop @last_verification = 0 message = "#{e.class.name}: #{e.message}: #{sql}" log_info(message, name, 0) raise ActiveRecord::StatementInvalid, message end def format_log_entry(message, dump = nil) if ActiveRecord::Base.colorize_logging if @@row_even @@row_even = false message_color, dump_color = "4;36;1", "0;1" else @@row_even = true message_color, dump_color = "4;35;1", "0" end log_entry = " \e[#{message_color}m#{message}\e[0m " log_entry << "\e[#{dump_color}m%#{String === dump ? 's' : 'p'}\e[0m" % dump if dump log_entry else "%s %s" % [message, dump] end end end end end