The relationship between the employee and the project is many-to-many in this scenario. Each project may involve more than one employee, and each employee may work on more than one project. You should use a junction (associative) table to handle the different billing rates. Table of Assignments: Employee ID (FK) Project ID (FK) Rate of Billing This table keeps track of the precise billing rate for every assignment and associates workers with projects. It guarantees clear tracking of all project assignments and billing information.