15 Questions Total

Relational Database Concepts MCQs

Topic-wise practice questions for Database Management Systems. Test your knowledge, check solutions on demand, and pace your preparation.

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Q1medium

Observe the SQL below. What is the Primary Key of the


Enrollments table?

sql-editor - composite_keys


CREATE TABLE Enrollments (
    student_id INT,

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Q2medium

According to the Entity Integrity Constraint, which of the following statements is true regarding a Primary Key?

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Q3hard

Consider the following table and data. What happens if you try to


execute: DELETE FROM Parent WHERE id = 1;?

postgres - delete_logic


CREATE TABLE Parent (id INT PRIMARY KEY);
CREATE TABLE Child (
    c_id INT PRIMARY KEY,
    p_id INT REFERENCES Parent(id) ON DELETE CASCADE
);
INSERT INTO Parent VALUES (1);

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Q4easy

In the relational model, why is it stated that "tuples are unordered"?

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Q5medium

An e-commerce database has a table Orders. The designer wants to ensure that the total_amount column never accepts negative values. Which relational concept should be applied?

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Q6medium

Consider a relation Employees(EmpID, Name, DeptID, Salary, Phone). Currently, there are 500 employee records. What are the Degree and the Cardinality of this relation?

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Q7medium

A relation R has attributes {A, B, C, D}. The only unique combinations of attributes are {A, B} and {A, C}. How many Candidate Keys does this relation have?

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Q8medium

What does the term "Domain" represent in a relational schema?


INSERT INTO Child VALUES (100, 1);

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Q9medium

A table ProjectAssignments uses a composite Primary Key consisting of (EmployeeID, ProjectID). If a manager tries to assign Employee 501 to Project 'A' twice, which error will the DBMS throw?

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Q10medium

If Relation A has 10 tuples and Relation B has 5 tuples, what is the Cardinality of the Cartesian Product (A x B)?

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