mysqlpp::BadQuery Class Reference

Exception thrown when the database server encounters a problem while processing your query. More...

#include <exceptions.h>

Inheritance diagram for mysqlpp::BadQuery:

[legend]Collaboration diagram for mysqlpp::BadQuery:

[legend]List of all members.

Public Member Functions
	BadQuery (const char *w="", int e=0)
	Create exception object.
	BadQuery (const std::string &w, int e=0)
	Create exception object.
int	errnum () const
	Return the error number corresponding to the error message returned by what().

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Detailed Description

Exception thrown when the database server encounters a problem while processing your query.

Unlike most other MySQL++ exceptions, which carry just an error message, this type carries an error number to preserve Connection::errnum()'s return value at the point the exception is thrown. We do this because when using the Transaction class, the rollback process that occurs during stack unwinding issues a query to the database server, overwriting the error value. This rollback should always succeed, so this effect can fool code that relies on Connection::errnum() into believing that there was no error.

Beware that in older versions of MySQL++, this was effectively the generic exception type. (This is most especially true in v1.7.x, but it continued to a lesser extent through the v2.x series.) When converting old code to new versions of MySQL++, it's therefore possible to get seemingly "new" exceptions thrown, which could crash your program if you don't also catch a more generic type like mysqlpp::Exception or std::exception.

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Constructor & Destructor Documentation

mysqlpp::BadQuery::BadQuery	(	const char *	w = "",
		int	e = 0
	)			[inline, explicit]

Create exception object.

Parameters:

	w	explanation for why the exception was thrown
	e	the error number from the underlying database API

mysqlpp::BadQuery::BadQuery	(	const std::string &	w,
		int	e = 0
	)			[inline, explicit]

Create exception object.

Parameters:

	w	explanation for why the exception was thrown
	e	the error number from the underlying database API

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Member Function Documentation

int mysqlpp::BadQuery::errnum

(

)

const [inline]

Return the error number corresponding to the error message returned by what().

This may return the same value as Connection::errnum(), but not always. See the overview documentation for this class for the reason for the difference.

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

• exceptions.h

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