Introduction to basics of PHP database operations

// 数据库信息
    $url = "192.168.199.146";    //$url = "localhost";
    $username = "root";    $password = "123123";    $db_name = "test";    // 获取数据
    $conn = new mysqli ( $url, $username, $password, $db_name );    if ($conn->connect_error) {        die ( "db connection error" );
    }    $start_rows = ($page-1) * $rows;    $sql = "SELECT * FROM user LIMIT " . $start_rows . "," . $rows;    $result = $conn->query ( $sql );    $jarr = array();    while ($rows=mysqli_fetch_array($result,MYSQL_ASSOC)){        $count=count($rows);//不能在循环语句中，由于每次删除 row数组长度都减小
        for($i=0;$i<$count;$i++){            unset($rows[$i]);//删除冗余数据
        }
        array_push($jarr,$rows);
    }    $jobj=new stdclass();//实例化stdclass，这是php内置的空类，可以用来传递数据，由于json_encode后的数据是以对象数组的形式存放的，
    //$jobj->total=$result->num_rows;//总数
    //获取总数
    $get_all_user_sql="SELECT count(*) as total FROM user";    $result_total = $conn->query ( $get_all_user_sql );    $rows_total=$result_total->fetch_assoc()["total"];    $jobj->total = $rows_total;    $jobj->rows=$jarr;    //所以我们生成的时候也要把数据存储在对象中
    /*foreach($jarr as $key=>$value){
        $jobj->$key=$value;
    }*/
    echo json_encode($jobj);

    $url = "192.168.199.146";    //$url="localhost";
    $username = "root";    $password = "123123";    $db_name = "test";    //连接数据库
    $conn = new mysqli ( $url, $username, $password, $db_name );    if ($conn->connect_error) {        die ( "db connection error" );
    }    //保存数据
    $insert_sql="INSERT user(name,password)";    $insert_sql=$insert_sql." VALUES('".$param['name']."','".$param['password']."')";    
    echo $insert_sql;    $result=$conn->query($insert_sql);    if($result===true){        echo "新记录插入成功";
    }else{        echo "插入新记录失败";
    }

// 数据库信息
    $url = "192.168.199.146";    //$url = "localhost";
    $username = "root";    $password = "123123";    $db_name = "test";    // 获取数据
    $conn = new mysqli ( $url, $username, $password, $db_name );    if ($conn->connect_error) {        die ( "db connection error" );
    }    $start_rows = ($page-1) * $rows;    $sql = "SELECT * FROM user LIMIT " . $start_rows . "," . $rows;    $result = $conn->query ( $sql );    $jarr = array();    while ($rows=mysqli_fetch_array($result,MYSQL_ASSOC)){        $count=count($rows);//不能在循环语句中，由于每次删除 row数组长度都减小
        for($i=0;$i<$count;$i++){            unset($rows[$i]);//删除冗余数据
        }
        array_push($jarr,$rows);
    }    $jobj=new stdclass();//实例化stdclass，这是php内置的空类，可以用来传递数据，由于json_encode后的数据是以对象数组的形式存放的，
    //$jobj->total=$result->num_rows;//总数
    //获取总数
    $get_all_user_sql="SELECT count(*) as total FROM user";    $result_total = $conn->query ( $get_all_user_sql );    $rows_total=$result_total->fetch_assoc()["total"];    $jobj->total = $rows_total;    $jobj->rows=$jarr;    //所以我们生成的时候也要把数据存储在对象中
    /*foreach($jarr as $key=>$value){
        $jobj->$key=$value;
    }*/
    echo json_encode($jobj);

    $url = "192.168.199.146";    //$url="localhost";
    $username = "root";    $password = "123123";    $db_name = "test";    //连接数据库
    $conn = new mysqli ( $url, $username, $password, $db_name );    if ($conn->connect_error) {        die ( "db connection error" );
    }    //保存数据
    $insert_sql="INSERT user(name,password)";    $insert_sql=$insert_sql." VALUES('".$param['name']."','".$param['password']."')";    
    echo $insert_sql;    $result=$conn->query($insert_sql);    if($result===true){        echo "新记录插入成功";
    }else{        echo "插入新记录失败";
    }