php封装msql 常用函数 增删改查 mysqli

<?php/** * Created by PhpStorm. * User: Administrator * Date: 2017/10/9 * Time: 9:58 *///require_once "../include.php";//require_once "../configs/configs.php";function connect(){    $mysqli = new mysqli('localhost', 'root', '', 'shopimooc');//var_dump($mysqli);    if ($mysqli->connect_error > 0) {        echo "连接错误";        echo $mysqli->connect_error;        exit;    }    $mysqli->query("SET NAMES UTF8");  //设置数据库字符集    return $mysqli;}function insert($table,$array){    $conn=connect();    $keys="".join(",",array_keys($array));    $vals="'".join("','",array_values($array))."'";    $sql="INSERT INTO {$table} ({$keys})VALUES ({$vals})";    if ($conn->query($sql) === TRUE) {        return null;    } else {        echo "Error: " . $sql . "<br>" . $conn->error;        return $sql;    }}function update($table,$array,$where=null){    $sql="update {$table} set cName='{$array}' ".($where==null?null:" where ").$where;//    如果没有传入判断条件，即为空，这里 $where==null? 为1   传入条件 即非空，那么执行传入的where 语句//update shop_admin set username= "king" where id=1//可以参照这句话    表达式1是否为真，如果为真，执行表达式2，要么执行表达式3   因为$where 为条件，例如id=1//所以是"where".$where    mysqli_query(connect(),$sql);    return mysqli_affected_rows(connect());}function delete($table,$where){    $where= $where==null?null:" where ".$where;    $sql ="delete from {$table}{$where}";    mysqli_query($sql);    return mysqli_affected_rows();}/*查找操作,查找一条记录*/function fetchOne($sql,$result_type=MYSQLI_ASSOC){    $result=mysqli_query(connect(),$sql);    if ($result->num_rows > 0) {        // 输出每行数据        while($row = $result->fetch_assoc()) {            return $row;        }    } else {        echo "0 个结果";    }}/*查找操作,获取所有记录*/function fetchAll($sql,$result_type=MYSQLI_ASSOC){    //$result_type = MYSQL_ASSOC这个返回的数组是以数据表中的字段为键的而MYSQL_NUM是以数字为键搜索的    $conn=connect();    $result=$conn->query($sql);    if ($result->num_rows > 0) {        // 输出每行数据        while($row = $result->fetch_assoc()) {            $rows[]=$row;        }    } else {        echo "0 个结果";    }    return $rows;}/*获取记录条数*/function getResultNum($sql){    $conn=connect();    $result=$conn->query($sql);    $totalRows=$result->num_rows;    return $totalRows;}