| 이름 | 설명 |
|---|---|
| Query | The `Query` class acts as a container for all information necessary to perform a particular database operation. Each `Query` object instance has a type, which is usually one of `'create'`, `'read'`, `'update'` or `'delete'`. |
| QueryException | The `QueryException` is thrown when a CRUD operation on the database returns an error. |
| Relationship | The `Relationship` class encapsulates the data and functionality necessary to link two model classes together. |
