UndoLog

Each session keeps a undo log if rollback is required.

Methods
	UndoLog(Session session) Create a new undo log for the given session.
	UndoLog(Session session) Create a new undo log for the given session. Parameters: session - the session
void	add(UndoLogRecord entry) Append an undo log entry to the log.
void	add(UndoLogRecord entry) Append an undo log entry to the log. Parameters: entry - the entry
void	clear() Clear the undo log.
void	clear() Clear the undo log. This method is called after the transaction is committed.
UndoLogRecord	getLast() Get the last record and remove it from the list of operations.
UndoLogRecord	getLast() Get the last record and remove it from the list of operations. Returns: the last record
Table	getTable(int id) Get the table for this id.
Table	getTable(int id) Get the table for this id. The table must be registered for this undo log first by calling getTableId. Parameters: id - the table id Returns: the table object
int	getTableId(Table table) Get the table id for this undo log.
int	getTableId(Table table) Get the table id for this undo log. If the table is not registered yet, this is done as well. Parameters: table - the table Returns: the id
void	removeLast(boolean trimToSize) Remove the last record from the list of operations.
void	removeLast(boolean trimToSize) Remove the last record from the list of operations. Parameters: trimToSize - if the undo array should shrink to conserve memory
void	seek(long filePos) Go to the right position in the file.
void	seek(long filePos) Go to the right position in the file. Parameters: filePos - the position in the file
int	size() Get the number of active rows in this undo log.
int	size() Get the number of active rows in this undo log. Returns: the number of rows