(PHP 4 = 4.0.6)
mysql_unbuffered_query() sends a
SQL query query to MySQL,
without fetching and buffering the result rows automatically,
as
mysql_query() does. On the one hand, this saves a
considerable amount of memory with SQL queries that produce
large result sets. On the other hand, you can start working
on the result set immediately after the first row has been
retrieved: you don't have to wait until the complete SQL
query has been performed. When using multiple DB-connects,
you have to specify the optional parameter link_identifier.
The optional
result_mode parameter can be MYSQL_USE_RESULT and
MYSQL_STORE_RESULT. It defaults to MYSQL_USE_RESULT, so the
result is not buffered. See also
mysql_query() for the counterpart of this
behaviour.
注: The benefits of mysql_unbuffered_query() come at a cost: You cannot use mysql_num_rows() on a result set returned from mysql_unbuffered_query(). You also have to fetch all result rows from an unbuffered SQL query, before you can send a new SQL query to MySQL.
See also: mysql_query().