This function cannot be used with any queries that return results. This includes SELECT, OPTIMIZE TABLE, etc.
(PHP 5 >= 5.1.0, PHP 7, PHP 8, PECL pdo >= 0.1.0)
PDO::exec — SQL ステートメントを実行し、作用した行数を返す
PDO::exec() は、一度の関数コールで SQL 文を実行し、文によって作用した行数を返します。
PDO::exec() は SELECT 文からは結果を返しません。 プログラム中で一度だけ発行が必要になる SELECT 文に対しては、 PDO::query() の発行を検討してください。 複数回発行が必要な文については、PDO::prepare() による PDOStatement オブジェクトの準備と PDOStatement::execute() による文の発行を行ってください。
PDO::exec() は、発行した SQL
ステートメントによって更新もしくは
削除された行数を返します。
1 行も作用しなかった場合、PDO::exec() は
0 を返します。
この関数は論理値
false を返す可能性がありますが、false として評価される値を返す可能性もあります。
詳細については 論理値の
セクションを参照してください。この関数の返り値を調べるには
===演算子 を
使用してください。
以下の例は PDO::exec() の戻り値の使用法を間違っています。結果として一行も更新されなかった場合に die() がコールされてしまうからです。
<?php
$db->exec() or die(print_r($db->errorInfo(), true)); // 間違っている
?>
PDO::ATTR_ERRMODE が PDO::ERRMODE_WARNING に設定されていた場合、E_WARNING レベルのエラーが発生します。
PDO::ATTR_ERRMODE が PDO::ERRMODE_EXCEPTION に設定されていた場合、PDOException がスローされます。
例1 DELETE 文の発行
WHERE 句を伴う DELETE 文によって削除された行数をカウントします。
<?php
$dbh = new PDO('odbc:sample', 'db2inst1', 'ibmdb2');
/* FRUIT テーブルから全ての行を削除する */
$count = $dbh->exec("DELETE FROM fruit");
/* 削除された行数を返す */
print "Deleted $count rows.\n";
?>上の例の出力は以下となります。
Deleted 1 rows.
This function cannot be used with any queries that return results. This includes SELECT, OPTIMIZE TABLE, etc.It's worth noting here, that - in addition to the hints given in docs up there - using prepare, bind and execute provides more benefits than multiply querying a statement: performance and security!
If you insert some binary data (e.g. image file) into database using INSERT INTO ... then it may boost performance of parsing your statement since it is kept small (a few bytes, only, while the image may be several MiBytes) and there is no need to escape/quote the file's binary data to become a proper string value.
And, finally and for example, if you want to get a more secure PHP application which isn't affectable by SQL injection attacks you _have to_ consider using prepare/execute on every statement containing data (like INSERTs or SELECTs with WHERE-clauses). Separating the statement code from related data using prepare, bind and execute is best method - fast and secure! You don't even need to escape/quote/format-check any data.PDO::eval() might return `false` for some statements (e.g. CREATE TABLE) even if the operation completed successfully, when using PDO_DBLIB and FreeTDS. So it is not a reliable way of testing the op status.
PDO::errorInfo() can be used to test the SQLSTATE error code for '00000' (success) and '01000' (success with warning).
<?php
function execute(PDO $conn, $sql) {
$affected = $conn->exec($sql);
if ($affected === false) {
$err = $conn->errorInfo();
if ($err[0] === '00000' || $err[0] === '01000') {
return true;
}
}
return $affected;
}
?>
PDO::errorInfo(): http://php.net/manual/en/pdo.errorinfo.php
List of SQLSTATE Codes: http://www-01.ibm.com/support/knowledgecenter/SSGU8G_11.70.0/com.ibm.sqls.doc/ids_sqs_0809.htmthis function don't execute multi_query
to get it see SQLITE_EXEC comments there is an pereg function that get all queries and execute all then an return the last oneNote that with MySQL you can detect a DUPLICATE KEY with INSERT (1 = INSERT, 2 = UPDATE) :
<?php
// MySQL specific INSERT UPDATE-like syntax
$sql = <<<SQL
INSERT INTO customers
SET
id = {$pdo->quote($id)},
name = {$pdo->quote($name)},
address = {$pdo->quote($address)}
AS new
ON DUPLICATE KEY UPDATE
name = new.name,
address = new.address
SQL;
$result = $pdo->exec($sql);
if ($result === 1) {
// An INSERT of a new row has be done
} elseif ($result === 2) {
// An UPDATE of an existing row has be done
}For those that want an exec that handles params like prepare/execute does. You can simulate this with another function
<?php
class Real_PDO extends PDO {
public function execParams($sql, $params) {
$stm = $this->prepare($sql);
$result = false;
if( $stm && $stm->execute($params) ) {
$result = $stm->rowCount();
while( $stm->fetch(PDO::FETCH_ASSOC) ) {
}
}
return $result;
}
}
?>
Remember though, if you are doing a lot of inserts, you'll want to do it the manual way, as the prepare statement will speed up when doing multiple executes(inserts). I use this so I can place all my SQL statements in one place, and have auto safe quoting against sql-injections.
If you are wondering about the fetch after, remember some databases can return data SELECT-like data from REMOVE/INSERTS. In the case of PostgreSQL, you can have it return you all records that were actually removed, or have the insert return the records after the insert/post field functions, and io trigger fire, to give you normalized data.
<?php
define("BLAH_INSERT", "INSERT INTO blah (id,data) VALUES(?,?)");
$pdo = new Real_PDO("connect string");
$data = array("1", "2");
$pdo->execParams(BLAH_INSERT, $data);
?>You can't use it not only with SELECT statement, but any statement that might return rows. "OPTIMIZE table" is such example (returns some rows with optimization status).
If you do, PDO will lock-up with the "Cannot execute queries while other unbuffered queries are active." nonsense.