???????????

????4 ??? VS ??
????????????????????:????????????????????????????????????????????????
?????????λ??????????????????????????????????????????????????????????????????????????
?????????????????????90?????????????
????????????????????--->??????---->????
???????????￡?????--->??????---->???????
????????????????????????????????????????????????
????class Person {
????public $name;
????public $age;
????public $sex;
????public $weight;
????}
?????????????Ь??????????
????id????int name????varchar(50) age????int sex????enum("??"??"?") weight??int
??????λ?Ь????????
???????????д??.
????$person1 = new Person();
????$person1->name = "????';
????$person2= new Person();
????$person2->name = "????';
??????λ?Ь??д????????
????id????int name????varchar(50) age????int sex????enum("??"??"?") weight??int
????1 ????
????2 ????
?????????????????Щ??????????????????????
?????????д????
????class Person {
????public $name;
????public $age;
????public $orders = array(new Order()??new Order());
????}
????class Order {
????public $money;
????public $items = array(
????"?????????????????????"??
????"?????????????"
????);
????}
????90???С????????????
????order???
????order_id???? person_id???? money
????order_item???
????item_id???? order_id???? item_name
??????????????????????????????????????????????????????????????????????
???????????????????Щ?Ь???????У???????????????Щ?Ь???
????5. ????? VS ???????
??????????? =>????? ??90?????????????????
??????????κ?????????????ν????????????????????????2??￡???????tinyint??char??varchar?????????????????????????????????????????????
???????????????????????е????????????????ж?????