mysql_query() also returns a resource for "OPTIMIZE TABLE" statements!
mysql_free_result
(PHP 4, PHP 5)
mysql_free_result — Free result memory
Warning
This extension is deprecated as of PHP 5.5.0, and will be removed in the future. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
- mysqli_free_result()
- Assign the value of
NULLto the PDO object, or PDOStatement::closeCursor()
說明
bool mysql_free_result
( resource
$result
)
mysql_free_result() will free all memory
associated with the result identifier result.
mysql_free_result() only needs to be called if you are concerned about how much memory is being used for queries that return large result sets. All associated result memory is automatically freed at the end of the script's execution.
回傳值
如果成功則回傳 TRUE，失敗則回傳 FALSE。
If a non-resource is used for the result, an
error of level E_WARNING will be emitted. It's worth noting that
mysql_query() only returns a resource
for SELECT, SHOW, EXPLAIN, and DESCRIBE queries.
範例
Example #1 A mysql_free_result() example
<?php
$result = mysql_query("SELECT id,email FROM people WHERE id = '42'");
if (!$result) {
echo 'Could not run query: ' . mysql_error();
exit;
}
/* Use the result, assuming we're done with it afterwards */
$row = mysql_fetch_assoc($result);
/* Now we free up the result and continue on with our script */
mysql_free_result($result);
echo $row['id'];
echo $row['email'];
?>
註釋
Note:
為了保證向前相容，可以使用下面的別名，但不贊成使用它： mysql_freeresult()
add a note
User Contributed Notes 3 notes
webmaster at bluesting dot co dot za ¶
13 years ago
admin at ifyouwantblood dot de ¶
16 years ago
yes this function may increase the memory usage if you use unbuffered querys and if you have not fetched all the data from mysql. in this case the mysql api has a problem: you want to free the result but do not want to close the connection. now mysql will only accept another query if all data has been fetched, so the api now must fetch the rest of the data when calling mysql_free_result().
so only use unbuffered querys if you fetch all the data (and need it).
