自己封装对数据库的一些操作

dbconn.php

<?php
	class DBConn{
		private static $servername = "localhost";
		private static $username = "root";
		private static $password = "root";
		private static $conn = null;
		function __construct(){
			try{
				self::$conn = new PDO("mysql:host=".self::$servername.";dbname=aa", self::$username, self::$password);
				echo "conn";
			}catch(PDOException $e){
				echo $e->getMessage();
			}
		}
		
		public static function getInstance(){
			if(self::$conn == null){
				new DBConn();
			}
			
			return self::$conn;
		}
		
		//查询
		public function query($sql, $param){
			try{
				$conn = self::getInstance();
				$stmt = $conn->prepare("select * from user limit :a,:b");
				//$rows = $conn->query("select * from user limit 1,2")->fetchAll(PDO::FETCH_ASSOC);
				$param = array("a"=>1,"b"=>2);
				//$a = 1;
				//$b = 2;
				//$stmt->bindValue(":a", $a, PDO::PARAM_INT);
				//$stmt->bindValue(":b", $b, PDO::PARAM_INT);
				$this->bindArrayValue($stmt, $param);
				$stmt->execute();
				$rows = $stmt->fetchAll(PDO::FETCH_ASSOC);
				print_r($rows);
			}catch(PDOException $e){
				print $e->getMessage();
			}
		}
		
		public function insert($sql, $param){
			try{
				$conn = self::getInstance();
				$stmt = $conn->prepare("select * from user limit :a,:b");
				//$rows = $conn->query("select * from user limit 1,2")->fetchAll(PDO::FETCH_ASSOC);
				$param = array("a"=>1,"b"=>2);
			}catch(PDOException $e){
				print $e->getMessage();
			}
		}
		
		public function execParams($sql, $params) { 
			$conn = self::getInstance();
			$stmt = $conn->prepare("update user set password = ? and name = ?"); 
			$result = false; 
			if( $stm && $stm->execute(array(4, 6)) ) { 
			  $result = $stm->rowCount(); 
			  while( $stm->fetch(PDO::FETCH_ASSOC) ) {
				print_r $stm->fetch(PDO::FETCH_ASSOC);
			  } 
			} 
			return $result; 
		} 

		
		//绑定数据类型
		public function bindArrayValue($stmt, $array, $typeArray = false){
			if(is_object($stmt) && ($stmt instanceof PDOStatement)){
				foreach($array as $key => $value){
					if($typeArray){
						$stmt->bindValue(":$key",$value,$typeArray[$key]);
					}else{
						if(is_int($value)) $param = PDO::PARAM_INT;
						elseif(is_bool($value)) $param = PDO::PARAM_BOOL;
						elseif(is_null($value)) $param = PDO::PARAM_NULL;
						elseif(is_string($value)) $param = PDO::PARAM_STR;
						else $param = FALSE;
						
						if($param) $stmt->bindValue(":$key",$value,$param);
					}
				}
			}
		}
		
		
		
	}
?>

dbdelete.php

dbhandle.php

<?php
	header('content-type:text/html;charset=utf-8');
	try{
		$conn = new PDO("mysql:host=127.0.0.1;dbname=aa","root","root");
		$rows = $conn->query('select * from user')->fetchAll(PDO::FETCH_OBJ);
		$rs = array();
		foreach($rows as $row){
			$rs[] = $row;
		}
		$db = null;
	}catch(PDOException $e){
		print $e->getMessage();
		die();
	}
	print_r($rs);
	print "<br/>";
	try{
		$conn = new PDO("mysql:host=127.0.0.1;dbname=aa","root","root");
		$stmt = $conn->prepare("select * from user limit :a,:b");
		$param = array("a"=>0,"b"=>2);
		
		bindArrayValue($stmt, $param);
		
		
		$stmt->execute();
		$rows = $stmt->fetchAll(PDO::FETCH_ASSOC);
		print_r($rows);
	}catch(PDOException $e){
		print $e->getMessage();
	}
	
	function bindArrayValue($req, $array, $typeArray = false)
	{
		if(is_object($req) && ($req instanceof PDOStatement))
		{
			foreach($array as $key => $value)
			{
				if($typeArray)
					$req->bindValue(":$key",$value,$typeArray[$key]);
				else
				{
					if(is_int($value))
						$param = PDO::PARAM_INT;
					elseif(is_bool($value))
						$param = PDO::PARAM_BOOL;
					elseif(is_null($value))
						$param = PDO::PARAM_NULL;
					elseif(is_string($value))
						$param = PDO::PARAM_STR;
					else
						$param = FALSE;
						
					if($param)
						$req->bindValue(":$key",$value,$param);
				}
			}
		}
	}


	
?>

dbinsert.php

<?php
	include "dbconn.php";
	
	class UserDao{
		
		public function insert(){
			$conn = DBConn::getInstance();
			$sql = "insert into user(id, name, password, address) values('2','2','2','2')";
			$conn->exec($sql);
			echo "</br>insert";
		}
		
	}
	
	$userDao = new UserDao();
	$userDao->insert();

?>

dbtest.php

<?php
	require_once("dbconn.php");
	
	$dbhelper = new DBConn();
	
	$dbhelper->query();
	
	
	$dbhelper->execParams("sql", $data); 

?>

dbupdate.php

<?php
	include "dbconn.php";
	
	class UserService{
		
		public function update(){
			$conn = DBConn::getInstance();
			$sql = "update user set name=3 where id=1";
			$conn->exec($sql);
			echo "</br>update";
		}
		
	}
	
	$userService = new UserService();
	$userService->update();
?>