11月27日—用类重写PDO操作函数

<?php
header('content-type:text/html;charset=utf-8');
class Db{
    public $dsn;
    public $user;
    public $pwd;
    public $pdo;
    public function __construct($dsn,$user,$pwd){
        $this->dsn = $dsn;
        $this->user = $user;
        $this->pwd = $pwd;
        $this->connect();
    }
    public function connect(){
        $this->pdo = new PDO($this->dsn,$this->user,$this->pwd);
    }
    public function select($sql){
        $stmt = $this->pdo->prepare($sql);
        if($stmt->execute()){
            $arr = $stmt->fetchAll(PDO::FETCH_ASSOC);
            return $arr;
        }else{
            return false;
        }
    }
    public function find($sql){
        $stmt = $this->pdo->prepare($sql);
        if ($stmt->execute()){
            if ($stmt->rowCount()>0){
                $arr = $stmt->fetch(PDO::FETCH_ASSOC);
                return $arr;
            }else{
                return false;
            }
        }else{
            return false;
        }
    }
    public function insert($sql){
        $stmt = $this->pdo->prepare($sql);
        if ($stmt->execute()){
            if ($stmt->rowCount()>0){
                return true;
            }else{
                return false;
            }
        }else{
            return false;
        }
    }
    public function update($sql){
        $stmt = $this->pdo->prepare($sql);
        if ($stmt->execute()){
            if ($stmt->rowCount()>0){
                return true;
            }else{
                return false;
            }
        }else{
            return false;
        }
    }
    public function delete($sql){
        $stmt = $this->pdo->prepare($sql);
        if ($stmt->execute()){
            if ($stmt->rowCount()>0){
                return true;
            }else{
                return false;
            }
        }else{
            return false;
        }
    }
    public function rows_count($sql){
        $stmt = $this->pdo->prepare($sql);
        if ($stmt->execute()){
            if ($stmt->rowCount()>0){
                $arr = $stmt->fetch(PDO::PARAM_INT);
                $row = $arr[0];
                return $row;
            }else{
                return false;
            }
        }else{
            return false;
        }
    }
}
$db = new Db('mysql:host=localhost;dbname=demo','root','root');
$selectSql = 'SELECT * FROM `student`';
$findSql = 'SELECT * FROM `student` WHERE studentId=4';
$insertSql = 'INSERT INTO `student` SET `name`="测试",`phone`="123456",`collegeId`=3';
$updateSql = 'UPDATE `student` SET `name`="测试",`phone`="123456",`collegeId`=3 WHERE studentId=7';
$deleteSql = 'DELETE FROM `student` WHERE studentId=8';
$rowSql = 'SELECT count(*) FROM `student`';
//查询所有数据
$selectArr = $db->select($selectSql);
if ($selectArr===false){
    print_r($selectArr);
}else{
    echo '查找全部数据失败';
}
//查询单条数据
$findArr = $db->find($findSql);
if ($findArr===false){
    print_r($findArr);
}else{
    echo '查找数据失败';
}
//新增数据
$insert = $db->insert($insertSql);
if ($insert){
    echo '新增成功';
}else{
    echo '新增失败';
}
//修改数据
$update = $db->update($updateSql);
if ($update){
    echo '编辑成功';
}else{
    echo '编辑失败';
}
//删除数据
$delete = $db->delete($deleteSql);
if ($delete){
    echo '删除成功';
}else{
    echo '删除失败';
}
//查询总记录数
$row = $db->rows_count($rowSql);
echo '共有:'.$row.'条数据';