[MVC][Model] Account & AccountManage

Account
    create <- 呼叫 SqlAccountManage.create
    create <- 呼叫 OracleAccountManage.create
    create <- 呼叫 AccessAccountManage.create

SqlAccount
    internal create
    internal update

宣告 internal的函數, 只能夠過 Account.create呼叫

Singleton

Singleton:
    static (物件)未建立就已存在, 不需要再去 new一個物件出來

ex:
class Cat
    static color = yellow

[computer A]
print(Cat.color)
yellow

[computer B]
print(Cat.color)
yellow

[computer C]
print(Cat.color)
yellow