业务逻辑层和数据访问层：循环依赖

I’m having a little Architecture problem. In my project I have a Business Logic Layer (BLL) that contains all my business rules, models and OO API for the interface. Each object has static methods like getById that return an instance of said object. Each object also has methods like save and, delete. This is very straightforward OO code.I’m having a little Architecture problem. In my