MySQL 8.0.31
Source Code Documentation
Foreign_key_error_handler Class Reference

An Internal_error_handler that converts errors related to foreign key constraint checks 'ER_NO_REFERENCED_ROW_2' and 'ER_ROW_IS_REFERENCED_2' to ER_NO_REFERENCED_ROW and ER_ROW_IS_REFERENCED based on privilege checks. More...

#include <error_handler.h>

Inheritance diagram for Foreign_key_error_handler:
[legend]

Public Member Functions

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

Private Attributes

handlerm_table_handler
 
THDm_thd
 

Additional Inherited Members

- Protected Member Functions inherited from Internal_error_handler
 Internal_error_handler ()
 
Internal_error_handlerprev_internal_handler () const
 
virtual ~Internal_error_handler ()=default
 

Detailed Description

An Internal_error_handler that converts errors related to foreign key constraint checks 'ER_NO_REFERENCED_ROW_2' and 'ER_ROW_IS_REFERENCED_2' to ER_NO_REFERENCED_ROW and ER_ROW_IS_REFERENCED based on privilege checks.

This prevents from revealing parent and child tables information respectively when the foreign key constraint check fails and user does not have privileges to access those tables.

Constructor & Destructor Documentation

◆ Foreign_key_error_handler()

Foreign_key_error_handler::Foreign_key_error_handler ( THD thd,
handler table_handler 
)
inline

Member Function Documentation

◆ handle_condition()

bool Foreign_key_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
thdthe calling thread
sql_errnothe error number for the condition raised.
sqlstatethe SQLSTATE for the condition raised.
levelthe severity level for the condition raised.
msgthe error message for the condition raised.
Returns
true if the condition is handled

Implements Internal_error_handler.

Member Data Documentation

◆ m_table_handler

handler* Foreign_key_error_handler::m_table_handler
private

◆ m_thd

THD* Foreign_key_error_handler::m_thd
private

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