PHP數據庫類

<?php

class Db{

    //私有靜態屬性存儲實例化對象自身
    private static $instance;

    //存儲PDO類的實例化
    private $pdo;

    //PDOStatement類
    private $stmt;

    //禁止外部實例化對象，鏈接數據庫
    private function __construct($config,$port,$charset){
        try{
            $this->pdo = new PDO('mysql:host='.$config['host'].';dbname='.$config['dbname'].';charset='.$charset.';port='.$port.'',$config['user'],$config['password']);
            //開始事務回滾的錯誤警告
            $this->pdo->setAttribute(PDO::ATTR_ERRMODE,PDO::ERRMODE_EXCEPTION);
        }catch(PDOException $e){
            echo 'msyql error: '.$e->getMessage();
        }

    }

    //外部實例化
    public static function getInstance($config,$port=3306,$charset='utf8'){
        if(!self::$instance instanceof Db){
            self::$instance = new self($config,$port,$charset);
        }

        return self::$instance;
    }

    //插入數據
    public function insertData($table,$data){
        //拼接插入的數據庫字段名
        $columns =  implode(',',array_keys($data));
        //憑藉插入的數據
        $values = ':'.implode(',:',array_keys($data));
        $sql = "insert into $table ($columns) values ($values)";

        //處理date數據格式
        $newdata = $this->doData($data);

        //預處理sql,執行添加數據操作
        $this->doSql($sql,$newdata);
        //成功執行後返回插入數據的id，失敗返回錯誤信息
        if($this->stmt->errorCode()==00000){
            return $this->pdo->lastInsertId();
        }else{
            return $this->stmt->errorInfo()[2];
        }
    }

    //更新數據
    public function updateData($table,$data,$where){

        //檢查需要更新的數據是否存在
        if(!$this->getOne($table,array_keys($data)[0],$where)){
            echo '需要更新的數據不存在';
            return false;
        }

        //檢查傳入的數據並且拼接成字符串
        if(is_array($data)){
            $columns = '';
            foreach($data as $k=>$v){
                $columns.= $k.'=:'.$k.',';
            }
            $columns=rtrim($columns,',');
        }

        //sql語句
        $sql = "UPDATE $table SET $columns WHERE ".$where;

        //傳入的數組處理成pdo定的數據格式[':user_name'=>'lisi',':user_age'=>39]
        $newdata = $this->doData($data);
        //預處理sql,執行添加數據操作
        $this->doSql($sql,$newdata);
        //沒有錯誤返回1，有錯誤返回錯誤信息
        if($this->stmt->errorCode()==00000){
            return 1;
        }else{
            return $this->stmt->errorInfo()[2];
        }
    }

    //查詢一條數據
    public function getOne($table,$fields,$where){
        //檢查傳入的字段是否是數組
        if(is_array($fields)){
            if(count($fields)>1){
                $columns=implode(',',$fields);
            }else{
                $columns=$fields[0];
            }   
        }else{
            $columns = $fields;
        }

        //查詢語句
        $sql = "SELECT $columns FROM $table WHERE ".$where.' LIMIT 1';
        //預處理sql,執行添加數據操作
        $this->doSql($sql);
        //獲得查詢的結果集
        $res = $this->stmt->fetch(PDO::FETCH_ASSOC);
        //如果沒有錯誤則返回查詢的結果集，否則返回錯誤信息
        if($this->stmt->errorCode()==00000){
            return $res;
        }else{
            return $this->stmt->errorInfo()[2];
        }   
    }

    //查詢多條數據
    public function getAll($table,$fields,$where=1){
        //檢查傳入的字段是否是數組
        if(is_array($fields)){
            if(count($fields)>1){
                $columns=implode(',',$fields);
            }else{
                $columns=$fields[0];
            }   
        }else{
            $columns = $fields;
        }

        //查詢語句
        $sql = "SELECT $columns FROM $table WHERE ".$where;
        //預處理sql,執行添加數據操作
        $this->doSql($sql);
        //獲得查詢的結果集
        $res = $this->stmt->fetchALL(PDO::FETCH_ASSOC);
        //如果沒有錯誤則返回查詢的結果集，否則返回錯誤信息
        if($this->stmt->errorCode()==00000){
            return $res;
        }else{
            return $this->stmt->errorInfo()[2];
        }   
    }

    //刪除數據
    public function delData($table,$where){
        //檢查需要更新的數據是否存在
        if(!$this->getOne($table,['*'],$where)){
            echo '需要刪除的數據不存在';
            return false;
        }
        if(!$where){
            echo '請添加刪除條件';
            return false;
        }
        $sql = "DELETE FROM $table WHERE ".$where;
        //預處理sql,執行添加數據操作
        $this->doSql($sql);
        //如果沒有錯誤則返回查詢的結果集，否則返回錯誤信息
        if($this->stmt->errorCode()==00000){
            return 1;
        }else{
            return $this->stmt->errorInfo()[2];
        }
    }

    //處理傳入的數據
    private function doData($data){
        foreach($data as $k=>$v){
            $newk = ':'.$k;
            $newdata[$newk]=$v;
        }
        return $newdata;
    }

    //執行sql操作
    function doSql($sql,$data=null){
        //預處理sql
        $this->stmt=$this->pdo->prepare($sql);
        //執行添加數據操作
        $this->stmt->execute($data);
    }

    //禁止外部克隆
    private function __clone(){}

}
$config = ['host'=>'127.0.0.1','dbname'=>'shop','user'=>'root','password'=>'root'];
$db = Db::getInstance($config,3306,'utf8');

//插入數據
$table= 'user';
$data=['user_name'=>'sunliang','user_age'=>28,'sex'=>1,'email'=>'[email protected]','password'=>md5(123456),'money'=>544545.34];
echo $db->insertData($table,$data);
// $sql = 'insert into (username,password) values (:username,password)';
// $stmt = $db->prepare($sql);
// $data = [':username'=>'lisi',':password'=>123456];
// $stmt->execute($data);

//修改數據
// $table = 'user';
// $data=['user_name'=>'sunliang','user_age'=>28,'email'=>'[email protected]'];
// $sql = "update user set user_name=:username,user_age=:user_age,email=:email where id = 1";
// echo $db->updateData($table,$data,'id=18');
// $stmt = $db->prepare($sql);
// $stmt->execute($data);

//查詢一條數據
// $table = 'user';
// $fields= ['user_name','id'];
// $sql = 'select user_name,email from user where id = 1';
// print_r($db->getOne($table,$fields,'id=2'));

//查詢多條數據
// $table = 'user';
// $fields= ['user_name','id'];
// $sql = 'select user_name,email from user where id = 1';
// print_r($db->getAll($table,$fields));

//刪除數據
// $table = 'user';
// echo $db->delData($table,'id=16');

簡單的數據庫類