MySQL Improved Extension (
Mysqli
)
2319
if (!($stmt = $mysqli->prepare("INSERT INTO test(id) VALUES (?)"))) {
echo "Prepare failed: (" . $mysqli->errno . ") " . $mysqli->error;
}
/* Prepared statement, stage 2: bind and execute */
$id = 1;
if (!$stmt->bind_param("i", $id)) {
echo "Binding parameters failed: (" . $stmt->errno . ") " . $stmt->error;
}
if (!$stmt->execute()) {
echo "Execute failed: (" . $stmt->errno . ") " . $stmt->error;
}
/* Prepared statement: repeated execution, only data transferred from client to server */
for ($id = 2; $id < 5; $id++) {
if (!$stmt->execute()) {
echo "Execute failed: (" . $stmt->errno . ") " . $stmt->error;
}
}
/* explicit close recommended */
$stmt->close();
/* Non-prepared statement */
$res = $mysqli->query("SELECT id FROM test");
var_dump($res->fetch_all());
?>
The above example will output:
array(4) {
[0]=>
array(1) {
[0]=>
string(1) "1"
}
[1]=>
array(1) {
[0]=>
string(1) "2"
}
[2]=>
array(1) {
[0]=>
string(1) "3"
}
[3]=>
array(1) {
[0]=>
string(1) "4"
}
}
Every prepared statement occupies server resources. Statements should be closed explicitly
immediately after use. If not done explicitly, the statement will be closed when the statement handle is
freed by PHP.
Using a prepared statement is not always the most efficient way of executing a statement. A prepared
statement executed only once causes more client-server round-trips than a non-prepared statement.
This is why the
SELECT
is not run as a prepared statement above.
Also, consider the use of the MySQL multi-INSERT SQL syntax for INSERTs. For the example, multi-
INSERT requires less round-trips between the server and client than the prepared statement shown
above.
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