3.6.3 Many-to-Many ( M:M ) Relationships
A many-to-many relationship is an association between two entities where any instance of
the first entity may be associated with zero, one, or more instances of the second, and vice
versa. following figure, shows many-to-many relationship between Teacher and Student.
Relationship is read as: "At any given event, each Teacher teaches zero to many students,
and each student is being taught by zero to many teachers."
This particular relationship has data associated with it as shown in the diamond on the dia-
gram. Data that belongs to a many-to-many relationship is called intersection data.