Database Reference
In-Depth Information
A recursive relationship is a relationship that starts and ends on the same entity. A one-
to-many recursive relationship describes a hierarchy, whereas a many-to-many relationship
describes a network. In a hierarchy, an entity instance has, at most, one parent. In a net-
work, an entity instance can have more than one parent.
Let's illustrate both types of recursive relationships using
Employee
. Here is a one-to-
many recursive example:
•
Each Employee may manage one or many Employees.
•
Each Employee may be managed by one Employee.
And here is a many-to-many recursive example:
