DATABASE DESIGN PROBLEMS. READ AND ANSWER ALL PLEASE. THANKS. ========= Which of
ID: 3728394 • Letter: D
Question
DATABASE DESIGN PROBLEMS. READ AND ANSWER ALL PLEASE. THANKS.
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Which of the following code will create a foreign key named fk honnors on the column honors_subject of table students? The constraint is that the values need to reference the values of table HonnorsSubjects, column honors_subject_id. A It's not possible to create a foreign key after you have created a table. B ALTER TABLE Students ADD CONSTRAINT k_honnors FOREIGN KEY (honors_subject) REFERENCES HonnorsSubjects (honors_subject_id); C ALTER TABLE ADD CONSTRAINT Students.fk honnors (honors_subject) FOREIGN KEY REFERENCES HonnorsSubjects (honors_subject); D ALTER TABLE FOREIGN KEY REFERENCES Students (honors_ subject) E None of the above HonnorsSubjects ADD CONSTRAINT ik_honnors (honors_subject_id)Explanation / Answer
The syntax for adding a foreign key constraint on column C in a table T referencing column C' on table T' is:
ALTER TABLE T ADD CONSTRAINT constraint_name FOREIGN KEY(C) REFERENCES T'(C');
From this, it is clear that option B is the right way to add a foreign key constraint on an already created table T.
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