The relationship between zoos and employees is missing from the tables in Figure 2.1. The line (and the descriptive text) says that a zoo has 0 or more employees and an employee has 0 or more zoos but there is no foreign key in either zoo or employee table.
Seems like you need +employee_id in the zoo table or +zoo_id in the employee table (or both?).
Actually, I just realized you are using this notation to represent a join table. Sorry - this can be ignored. Thanks for the good read.
The relationship between zoos and employees is missing from the tables in Figure 2.1. The line (and the descriptive text) says that a zoo has 0 or more employees and an employee has 0 or more zoos but there is no foreign key in either zoo or employee table.
Seems like you need+employee_idin the zoo table or+zoo_idin the employee table (or both?).Actually, I just realized you are using this notation to represent a join table. Sorry - this can be ignored. Thanks for the good read.