RDBM MySQL Foregin密钥约束多项选择

Question

im just going through some past tests for one of my classes and came against this question

Consider the following foreign key declaration in a table X.

FOREIGN KEY a REFERENCES Y (b)

This declaration:

(a) establishes a master-detail relationship between master records in b and detail records in a

(b) establishes a master-detail relationship between master records in X and detail records in Y

(c) establishes a master-detail relationship between master records in Y and detail records in X

(d) establishes a master-detail relationship between master records in a and detail records in b

I understand that a Master represents lets say a "User" while detail as "User's Friends"

is the answer d?

Answer 1

a = a field in table xb = a field in table y

so if a master has details you put this in the details create script

FOREIGN KEY M_id REFERENCES Master(id)

so the master table is Y and the detail table is X a = detail M_id b = master id

so the answer is C