An Internal_error_handler that suppresses errors regarding views' underlying tables that occur during privilege checking. More...

Inheritance diagram for View_error_handler:

Public Member Functions
	View_error_handler (Table_ref *top_view)

bool	handle_condition (THD thd, uint sql_errno, const char , Sql_condition::enum_severity_level level, const char message) override
	Handle a sql condition. More...

Additional Inherited Members
Protected Member Functions inherited from Internal_error_handler
	Internal_error_handler ()

Internal_error_handler *	prev_internal_handler () const

virtual	~Internal_error_handler ()=default

Detailed Description

An Internal_error_handler that suppresses errors regarding views' underlying tables that occur during privilege checking.

It hides errors which show view underlying table information. This happens in the cases when

A view's underlying table (e.g. referenced in its SELECT list) does not exist or columns of underlying table are altered. There should not be an error as no attempt was made to access it per se.
Access is denied for some table, column, function or stored procedure such as mentioned above. This error gets raised automatically, since we can't untangle its access checking from that of the view itself.

There are currently two mechanisms at work that handle errors for views based on an Internal_error_handler. This one and another one is Show_create_error_handler. The latter handles errors encountered during execution of SHOW CREATE VIEW, while this mechanism using this method is handles SELECT from views. The two methods should not clash.

Constructor & Destructor Documentation

View_error_handler::View_error_handler ( Table_ref * top_view )

inline

bool View_error_handler::handle_condition	(	THD *	thd,
		uint	sql_errno,
		const char *	sqlstate,
		Sql_condition::enum_severity_level *	level,
		const char *	msg
	)

overridevirtual

Handle a sql condition.

This method can be implemented by a subclass to achieve any of the following:

mask a warning/error internally, prevent exposing it to the user,
mask a warning/error and throw another one instead. When this method returns true, the sql condition is considered 'handled', and will not be propagated to upper layers. It is the responsibility of the code installing an internal handler to then check for trapped conditions, and implement logic to recover from the anticipated conditions trapped during runtime.

This mechanism is similar to C++ try/throw/catch:

'try' correspond to THD::push_internal_handler(),
'throw' correspond to my_error(), which invokes my_message_sql(),
'catch' correspond to checking how/if an internal handler was invoked, before removing it from the exception stack with THD::pop_internal_handler().

Parameters

thd	the calling thread
sql_errno	the error number for the condition raised.
sqlstate	the SQLSTATE for the condition raised.
level	the severity level for the condition raised.
msg	the error message for the condition raised.

Table_ref* View_error_handler::m_top_view

private

The documentation for this class was generated from the following files: