6.4.28 mysql_stmt_store_result()

int
mysql_stmt_store_result(MYSQL_STMT *stmt)

Description

Result sets are produced by calling mysql_stmt_execute() to executed prepared statements for SQL statements such as SELECT, SHOW, DESCRIBE, and EXPLAIN. By default, result sets for successfully executed prepared statements are not buffered on the client and mysql_stmt_fetch() fetches them one at a time from the server. To cause the complete result set to be buffered on the client, call mysql_stmt_store_result() after binding data buffers with mysql_stmt_bind_result() and before calling mysql_stmt_fetch() to fetch rows. (For an example, see Section 6.4.11, “mysql_stmt_fetch()”.)

mysql_stmt_store_result() is optional for result set processing, unless you will call mysql_stmt_data_seek(), mysql_stmt_row_seek(), or mysql_stmt_row_tell(). Those functions require a seekable result set.

It is unnecessary to call mysql_stmt_store_result() after executing an SQL statement that does not produce a result set, but if you do, it does not harm or cause any notable performance problem. You can detect whether the statement produced a result set by checking whether mysql_stmt_result_metadata() returns NULL. For more information, refer to Section 6.4.23, “mysql_stmt_result_metadata()”.

Note

MySQL does not by default calculate MYSQL_FIELD->max_length for all columns in mysql_stmt_store_result() because calculating this would slow down mysql_stmt_store_result() considerably and most applications do not need max_length. If you want max_length to be updated, you can call mysql_stmt_attr_set(MYSQL_STMT, STMT_ATTR_UPDATE_MAX_LENGTH, &flag) to enable this. See Section 6.4.3, “mysql_stmt_attr_set()”.

Return Values

Zero for success. Nonzero if an error occurred.

Errors

• CR_COMMANDS_OUT_OF_SYNC

  Commands were executed in an improper order.

• CR_OUT_OF_MEMORY

  Out of memory.

• CR_SERVER_GONE_ERROR

  The MySQL server has gone away.

• CR_SERVER_LOST

  The connection to the server was lost during the query.

• CR_UNKNOWN_ERROR

  An unknown error occurred.