简单的pgsql pdo php操作类实现代码

核心代码：

class pgdb {


 public $pdo;
 public static $PDOInstance;
 public $config;
 public $data;
 public $filed = '*';
 public $table;
 public $limit;
 public $order;
 public $where;
 public $left;


 const LOGIN = 7;
 const USER = 1;
 const GROUP = 2;
 const USERGROUP = 3;
 const LOG = 6;
 const WARING = 1;
 const ERROR = 2;
 const INFO = 0;


 public function __construct() {
  if (!self::$PDOInstance) {
    $this->config = json_decode(file_get_contents("./config/db.json"), true);


    $config = $this->config;
    $host = $config["data_base"]["db_host"];
    $dbname = $config["data_base"]["db_name"];
    $port = $config["data_base"]["db_port"];
    $username = $config["data_base"]["db_user"];
    $password = $config["data_base"]["db_pwd"];


    if ($config["data_base"]["db_host"] != 'localhost') {
      $hosturl = "host=$host;";
    }
    try
    {
      self::$PDOInstance = new PDO("pgsql:"
 . $hosturl
 . "port=$port;"
 . "dbname=$dbname;"
 , $username
 , $password
 , array(
   PDO::ATTR_PERSISTENT => true,
 )
      );
    } catch (Exception $ex) {
      header("Content-type: text/html; charset=utf-8");
      $error = "数据库初始化失败，已强制断开链接。
抓取到的异常栈如下：
" . print_r($ex, true) . "
";
      die($error);
    }
    try {
      self::$PDOInstance->query("SET client_encoding='UTF-8';");
      self::$PDOInstance->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
      self::$PDOInstance->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
     } catch (Exception $exc) {
     $this->pdo=NULL;
     $doc = <<
     
      
 
 
 
      
     
DOC;


    print $doc;
    $info=L('服务器变更请刷新');
    print("");
    print('');
    exit();
    }
   }
  
   $this->pdo = self::$PDOInstance;
  }
}