Author Question: What are the four sets of minimum cardinalities that can be present in a 1:N binary relationship? ... (Read 120 times)

stock · **on:** Jul 7, 2018

What are the four sets of minimum cardinalities that can be present in a 1:N binary relationship?

What will be an ideal response?

Question 2

Google's Bigtable was an early example of structured storage.

Indicate whether the statement is true or false

Tonny · **Reply #1 on:** Jul 7, 2018

Answer to Question 1

If we use the labels Parent and Child to represent, respectively, the one and many side of a 1:N relationship, we can then consider whether the parent and child must participate in the relationship. If one must participate, it is mandatory (M). If one does not have to participate it is optional (O). The four possible sets of minimum cardinalities are therefore:

Parent optional and Child optional (O-O)
Parent mandatory and Child optional (M-O)
Parent optional and Child mandatory (O-M)
Parent mandatory and Child mandatory (M-M)

Answer to Question 2

TRUE