Question

我使用PDO连接到我的数据库，我不知道哪个方法比UPDATE，DELETE和INSERT，PDO :: exec或PDO :: excute更好。我应该使用哪种？

Answer 1

虽然两种方法都有类似的命名（exec，execute），但它们意味着在不同的场景中使用：

exec用于获取受影响的行数。

/**
 * (PHP 5 &gt;= 5.1.0, PECL pdo &gt;= 0.1.0)<br/>
 * Execute an SQL statement and return the number of affected rows
 * @link http://php.net/manual/en/pdo.exec.php
 * @param string $statement <p>
 * The SQL statement to prepare and execute.
 * </p>
 * <p>
 * Data inside the query should be properly escaped.
 * </p>
 * @return int <b>PDO::exec</b> returns the number of rows that were modified
 * or deleted by the SQL statement you issued. If no rows were affected,
 * <b>PDO::exec</b> returns 0.
 * </p>
 * This function may
 * return Boolean <b>FALSE</b>, but may also return a non-Boolean value which
 * evaluates to <b>FALSE</b>. Please read the section on Booleans for more
 * information. Use the ===
 * operator for testing the return value of this
 * function.
 * <p>
 * The following example incorrectly relies on the return value of
 * <b>PDO::exec</b>, wherein a statement that affected 0 rows
 * results in a call to <b>die</b>:
 * <code>
 * $db->exec() or die(print_r($db->errorInfo(), true));
 * </code>
 */
public function exec ($statement) {}

示例：

$myQuery = "UPDATE users SET email = 'testing'";
$affectedRows = $db->exec($myQuery);

execute。

/**
 * (PHP 5 &gt;= 5.1.0, PECL pdo &gt;= 0.1.0)<br/>
 * Executes a prepared statement
 * @link http://php.net/manual/en/pdostatement.execute.php
 * @param array $input_parameters [optional] <p>
 * An array of values with as many elements as there are bound
 * parameters in the SQL statement being executed.
 * All values are treated as <b>PDO::PARAM_STR</b>.
 * </p>
 * <p>
 * You cannot bind multiple values to a single parameter; for example,
 * you cannot bind two values to a single named parameter in an IN()
 * clause.
 * </p>
 * <p>
 * You cannot bind more values than specified; if more keys exist in
 * <i>input_parameters</i> than in the SQL specified
 * in the <b>PDO::prepare</b>, then the statement will
 * fail and an error is emitted.
 * </p>
 * @return bool <b>TRUE</b> on success or <b>FALSE</b> on failure.
 */
public function execute (array $input_parameters = null) {}

示例（当然这也可能是UPDATE或DELETE查询）：

$myQuery = 'SELECT * FROM users WHERE username = :username';
$params = array(':username' => 'admin');
$db->query($myQuery)->execute($params);

query会返回PDOStatement个对象

/**
 * (PHP 5 &gt;= 5.1.0, PECL pdo &gt;= 0.2.0)<br/>
 * Executes an SQL statement, returning a result set as a PDOStatement object
 * @link http://php.net/manual/en/pdo.query.php
 * @param string $statement <p>
 * The SQL statement to prepare and execute.
 * </p>
 * <p>
 * Data inside the query should be properly escaped.
 * </p>
 * @return PDOStatement <b>PDO::query</b> returns a PDOStatement object, or <b>FALSE</b>
 * on failure.
 */
public function query ($statement) {}

有关详细信息，请访问PHP Docs，或者如果您使用PHPStorm，则可以查看PDO.php类的源代码。

PDO :: exec或PDO ::执行？

1 个答案: