Solution:Step 1: Analyze primary keys and uniquenessStudentProfile has ProfileID PRIMARY KEY and StudentID UNIQUE FOREIGN KEY referencing Student.Step 2: Identify enforcement mechanismUNIQUE on StudentID prevents duplicate StudentIDs, allowing only one profile per student while FK ensures referentia

[Solved] Given these tables:CREATE TABLE Student (StudentID INT PRIMARY KEY, Name VARCHAR(50));CREATE TABLE StudentProfile (ProfileID INT PRIMARY KEY, StudentID INT UNIQUE, FOREIGN KEY (StudentID) REFERENCES... | SQL

SQL - Table Relationships

Given these tables:
CREATE TABLE Student (StudentID INT PRIMARY KEY, Name VARCHAR(50));
CREATE TABLE StudentProfile (ProfileID INT PRIMARY KEY, StudentID INT UNIQUE, FOREIGN KEY (StudentID) REFERENCES Student(StudentID));
Why does this design enforce a one-to-one relationship?

AStudentProfile.ProfileID is separate primary key, allowing multiple profiles per student

BStudentID in StudentProfile is UNIQUE, so only one profile per student

CForeign key is missing in StudentProfile

DStudent table lacks UNIQUE constraint

Step-by-Step Solution

Solution:

Step 1: Analyze primary keys and uniqueness
StudentProfile has ProfileID PRIMARY KEY and StudentID UNIQUE FOREIGN KEY referencing Student.
Step 2: Identify enforcement mechanism
UNIQUE on StudentID prevents duplicate StudentIDs, allowing only one profile per student while FK ensures referential integrity.
Final Answer:
StudentID in StudentProfile is UNIQUE, so only one profile per student -> Option B
Quick Check:
UNIQUE on FK enforces one-to-one [OK]

Quick Trick: UNIQUE on FK enforces one-to-one even with surrogate PK [OK]

Common Mistakes:

MISTAKES

Thinking separate PK allows multiple profiles per student
Ignoring UNIQUE constraint on foreign key
Confusing missing foreign key with design issue

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More SQL Quizzes

Given these tables:

Step 1: Analyze primary keys and uniqueness

Step 2: Identify enforcement mechanism

Final Answer:

Quick Check:

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