Eine kurze Einführung in die Definitionsmethode und Verwendung der öffentlichen PDO-Klasse in PHP

In diesem Artikel werden hauptsächlich die Definition und Verwendung der von PHP implementierten öffentlichen PDO-Klasse vorgestellt und die von PHP implementierten PDO-Operationsklassendefinitionen sowie Abfrage-, Einfügungs- und andere Verwendungstechniken anhand spezifischer Beispiele analysiert

Das Beispiel in diesem Artikel beschreibt die Definition und Verwendung der von PHP implementierten öffentlichen Klasse pdo. Teilen Sie es als Referenz mit allen wie folgt:

db.class.php:

<?php
class db extends \PDO {
  private static $_instance = null;
  protected $dbName = &#39;&#39;;
  protected $dsn;
  protected $dbh;
  public function __construct($dbHost, $dbUser, $dbPasswd, $dbName, $dbCharset=&#39;utf8&#39;) {
    try {
      $this->dsn = &#39;mysql:host=&#39; . $dbHost . &#39;;dbname=&#39; . $dbName;
      $this->dbh = new \PDO($this->dsn, $dbUser, $dbPasswd);
      $this->dbh->setAttribute(\PDO::ATTR_EMULATE_PREPARES, false);
      $this->dbh->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
      $this->dbh->exec(&#39;SET character_set_connection=&#39;.$dbCharset.&#39;;SET character_set_client=&#39;.$dbCharset.&#39;;SET character_set_results=&#39;.$dbCharset);
    } catch (Exception $e) {
      $this->outputError($e->getMessage()); 
    }
  }
  public static function getInstance($dbHost, $dbUser, $dbPasswd, $dbName, $dbCharset=&#39;utf8&#39;) {
    if (self::$_instance === null) {
      self::$_instance = new self($dbHost, $dbUser, $dbPasswd, $dbName, $dbCharset);
    }
    return self::$_instance;
  }
  public function fetchAll($sql, $params = array()) {
    try {
      $stm = $this->dbh->prepare($sql);
      if ($stm && $stm->execute($params)) {
        return $stm->fetchAll(\PDO::FETCH_ASSOC);
      }
    } catch (Exception $e) {
      $this->outputError($e->getMessage());
    }
  }
  public function fetchOne($sql, $params = array()) {
    try {
      $result = false;
      $stm = $this->dbh->prepare($sql);
      if ($stm && $stm->execute($params)) {
        $result = $stm->fetch(\PDO::FETCH_ASSOC);
      }
      return $result;
    } catch (Exception $e) {
      $this->outputError($e->getMessage());
    }
  }
  public function fetchColumn($sql, $params = array()) {
    $result = &#39;&#39;;
    try {
      $stm = $this->dbh->prepare($sql);
      if ($stm && $stm->execute($params)) {
        $result = $stm->fetchColumn();
      }
      return $result;
    } catch (Exception $e) {
      $this->outputError($e->getMessage());
    }
  }
  public function insert($table, $params = array(), $returnLastId = true) {
    $_implode_field = &#39;&#39;;
    $fields = array_keys($params);
    $_implode_field = implode(&#39;,&#39;, $fields);
    $_implode_value = &#39;&#39;;
    foreach ($fields as $value) {
      $_implode_value .= &#39;:&#39;. $value.&#39;,&#39;;
    }
    $_implode_value = trim($_implode_value, &#39;,&#39;);
    $sql = &#39;INSERT INTO &#39; . $table . &#39;(&#39; . $_implode_field . &#39;) VALUES (&#39;.$_implode_value.&#39;)&#39;;
    try {
      $stm = $this->dbh->prepare($sql);
      $result = $stm->execute($params);
      if ( $returnLastId ) {
        $result = $this->dbh->lastInsertId();
      }
      return $result;
    } catch (Exception $e) {
      $this->outputError($e->getMessage());
    }
  }
  public function update($table, $params = array(), $where = null) {
    $_implode_field = &#39;&#39;;
    $_implode_field_arr = array();
    if ( empty($where) ) {
      return false;
    }
    $fields = array_keys($params);
    foreach ($fields as $key) {
      $_implode_field_arr[] = $key . &#39;=&#39; . &#39;:&#39;.$key;
    }
    $_implode_field = implode(&#39;,&#39;, $_implode_field_arr);
    $sql = &#39;UPDATE &#39; . $table . &#39; SET &#39; . $_implode_field . &#39; WHERE &#39; . $where;
    try {
      $stm = $this->dbh->prepare($sql);
      $result = $stm->execute($params);
      return $result;
    } catch (Exception $e) {
      $this->outputError($e->getMessage());
    }
  }
  public function delete($sql, $params = array()) {
    try {
      $stm = $this->dbh->prepare($sql);
      $result = $stm->execute($params);
      return $result;
    } catch (Exception $e) {
      $this->outputError($e->getMessage());
    }
  }
  public function exec($sql, $params = array()) {
    try {
      $stm = $this->dbh->prepare($sql);
      $result = $stm->execute($params);
      return $result;
    } catch (Exception $e) {
      $this->outputError($e->getMessage());
    }
  }
  private function outputError($strErrMsg) {
    throw new Exception("MySQL Error: " . $strErrMsg);
  }
  public function __destruct() {
    $this->dbh = null;
  }
}

Beispiel:

<?php
require_once &#39;./db.class.php&#39;;
$pdo = db::getInstance(&#39;127.0.0.1&#39;, &#39;root&#39;, &#39;111111&#39;, &#39;php_cms&#39;);
$sql = "select id, title1 from cms_wz where id = :id limit 1";
$parame = array(&#39;id&#39; => 12,);
$res = $pdo->fetchOne($sql, $parame);
var_dump($res);
$sql = &#39;SELECT * FROM cms_link&#39;;
$result = $db->fetchAll($sql);
print_r($result);
//查询记录数量
$sql = &#39;SELECT COUNT(*) FROM cms_link&#39;;
$count = $db->fetchColumn($sql);
echo $count;
$data = array(
  &#39;siteid&#39; => 1,
  &#39;linktype&#39; => 1,
  &#39;name&#39; => &#39;google&#39;,
  &#39;url&#39; => &#39;http://www.google.com&#39;,
  &#39;listorder&#39; => 0,
  &#39;elite&#39; => 0,
  &#39;passed&#39; => 1,
  &#39;addtime&#39; => time()
  );
$lastInsertId = $db->insert(&#39;cms_link&#39;, $data);
echo $lastInsertId;
//用 try
 try {
     $result = $pdo->insert(&#39;news&#39;, $essay);
   } catch (Exception $e) {
     error_log($e->getMessage());
     error_log($e->getMessage() . &#39; in &#39; . __FILE__ . &#39; on line &#39; . __LINE__);
     saveLog(&#39;url文章 : &#39; . $essay[&#39;link&#39;] . &#39;  数据插入失败<br>&#39;);
     continue;
   }
$data = array(
  &#39;siteid&#39; => 1,
  &#39;linktype&#39; => 1,
  &#39;name&#39; => &#39;google&#39;,
  &#39;url&#39; => &#39;http://www.google.com&#39;,
  &#39;listorder&#39; => 0,
  &#39;elite&#39; => 0,
  &#39;passed&#39; => 1,
  &#39;addtime&#39; => time()
  );
$db->insert(&#39;cms_link&#39;, $data);
$sql = &#39;DELETE FROM cms_link WHERE linkid=4&#39;;
$result = $db->delete($sql);
var_dump($result);

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