Prepared_statement Class Reference

List of all members.

Public Types
enum	flag_values { IS_IN_USE = 1, IS_SQL_PREPARE = 2 }
Public Member Functions
	Prepared_statement (THD *thd_arg)
virtual	~Prepared_statement ()
void	setup_set_params ()
virtual Query_arena::Type	type () const
virtual void	cleanup_stmt ()
bool	set_name (LEX_STRING *name)
void	close_cursor ()
bool	is_in_use ()
bool	is_sql_prepare () const
void	set_sql_prepare ()
bool	prepare (const char *packet, uint packet_length)
bool	execute_loop (String *expanded_query, bool open_cursor, uchar *packet_arg, uchar *packet_end_arg)
bool	execute_server_runnable (Server_runnable *server_runnable)
void	deallocate ()
Public Attributes
THD *	thd
Select_fetch_protocol_binary	result
Item_param **	param_array
Server_side_cursor *	cursor
uint	param_count
uint	last_errno
uint	flags
char	last_error [MYSQL_ERRMSG_SIZE]
bool(*	set_params )(Prepared_statement *st, uchar *data, uchar *data_end, uchar *read_pos, String *expanded_query)
bool(*	set_params_from_vars )(Prepared_statement *stmt, List< LEX_STRING > &varnames, String *expanded_query)

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Detailed Description

Prepared_statement: a statement that can contain placeholders.

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Constructor & Destructor Documentation

Prepared_statement::~Prepared_statement

(

)

[virtual]

Destroy this prepared statement, cleaning up all used memory and resources.

This is called from ::deallocate() to handle COM_STMT_CLOSE and DEALLOCATE PREPARE or when THD ends and all prepared statements are freed.

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Member Function Documentation

void Prepared_statement::deallocate

(

)

Common part of DEALLOCATE PREPARE and mysqld_stmt_close.

bool Prepared_statement::execute_loop	(	String *	expanded_query,
		bool	open_cursor,
		uchar *	packet,
		uchar *	packet_end
	)

Execute a prepared statement. Re-prepare it a limited number of times if necessary.

Try to execute a prepared statement. If there is a metadata validation error, prepare a new copy of the prepared statement, swap the old and the new statements, and try again. If there is a validation error again, repeat the above, but perform no more than MAX_REPREPARE_ATTEMPTS.

Note:

We have to try several times in a loop since we release metadata locks on tables after prepared statement prepare. Therefore, a DDL statement may sneak in between prepare and execute of a new statement. If this happens repeatedly more than MAX_REPREPARE_ATTEMPTS times, we give up.

Returns:

TRUE if an error, FALSE if success

Return values:

TRUE	either MAX_REPREPARE_ATTEMPTS has been reached, or some general error
FALSE	successfully executed the statement, perhaps after having reprepared it a few times.

bool Prepared_statement::prepare	(	const char *	packet,
		uint	packet_len
	)

Parse statement text, validate the statement, and prepare it for execution.

You should not change global THD state in this function, if at all possible: it may be called from any context, e.g. when executing a COM_* command, and SQLCOM_* command, or a stored procedure.

Parameters:

packet	statement text
packet_len

Note:

Precondition: The caller must ensure that thd->change_list and thd->free_list is empty: this function will not back them up but will free in the end of its execution.

Postcondition: thd->mem_root contains unused memory allocated during validation.

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

• sql_prepare.cc