Examen
CMPUT 291 Final Examination over view question – Dec University of Alberta
- Grado
- Institución
CMPUT 291 Final Examination over view question – Dec University of Alberta
[Mostrar más]Vista previa 3 fuera de 16 páginas
Vista previa 3 fuera de 16 páginas
Añadir al carrito
Vista previa del contenido
CMPUT 291 Final Examination over view question – Dec University of Alberta Section: A1 Name Signature Instructions: 1. Turn off your cell phone. 2. Sign your name on the signature line. 3. Place your student id number in the designated spot on the top of the next page. 4. The time for this test is 3 hours. 5. The exam is “closed -book”, i.e., no references, notes, books, calculators, or smart phones are allowed. 6. Place all answers in this booklet and do not hand in any other work. CMPUT 291 Midterm Exam Page 2 of 16 Student Id Number: Marks obtained: Part 1 Part 2 Part 3 Part 4 Total /20 /20 /30 /20 /90 Part 1 [20 marks] 1. [4 marks] Consider the following statements about data models for databases: 1. Logical Data Independence means that data can be accessed independently and concurrently by different users. 2. Physical data independence means that the physical schema can be changed without changing applications. 3. Physical data independence means that the conceptual schema can be changed without changing the physical schema . 4. Physical Data Independence is a special case of Logical Data Independence. Which of the following assertions is correct? Select only one. Statements 1, 2, and 4 are correct, and statement 3 is incorrect. Statements 2 and 4 are correct, and statements 1 and 3 are incorrect. Statements 3 and 4 are correct, and statements 1 and 2 are incorrect. Statement 2 is correct, and statements 1, 3 and 4 are incorrect. Statement 3, is correct, and statements 1, 2, and 4 are incorrect. All are correct. All are incorrect. CMPUT 291 Midterm Exam Page 3 of 16 2. [4 marks] Consider the following statements related to keys: 1. If a superkey consists of only one attribute, then the superkey must also be a candidate key. 2. If a superkey consists of more than one attribute, then it cannot be a candidate key because it is not minimal. 3. Assume a relation R(A,B,C,D) where all fields are numeric and A is the primary key. The following two SQL statements always return the same result: - select C from R where C = 2*A - select distinct C from R where C = 2*A 4. Every Relation has at least one key. Which of the following assertions is correct? Select only one. Statements 1, 2, are correct, and statements 3 and 4 are incorrect. Statements 1 and 3 are correct, and statements 2 and 3 are incorrect. Statements 2 and 3 are correct, and statements 1 and 4 are incorrect. Statements 1, 3, 4 are correct, and statement 2 is incorrect. Statements 1, 2, 3 are correct, and statement 4 is incorrect. All are correct. All are incorrect. 3. [4 marks] Consider the following statements about NULL values: 1. If no attribute of a relation is allowed to contain NULL values, then the combination of all attributes is a candidate key for that relation. 2. A field with a foreign key constraint can contain NULL values. 3. Assume that A is equal to NULL, B is equal to 70, and C is equal to 30. Then, the following expression evaluates to unknown : NOT ( (A > B) OR (B+C = 100) ). 4. Assume that A is equal to NULL, B is equal to 70, and C is equal to 30. Then, the following expression evaluates to unknown : ( (A < B) AND (B+C = 100) ). Which of the following assertions is correct? Select only one. Statements 1, 2, and 4 are correct, and statement 3 is incorrect. Statements 2, 3, and 4 are correct, and statement 1 is incorrect. Statements 3 and 4 are correct, and statements 1 and 2 are incorrect. Statements 2 and 4 are correct, and statements 1 and 3 are incorrect. Statement 2 is correct, and statements 1, 3, and 4 are incorrect. All are correct. All are incorrect.Los beneficios de comprar resúmenes en Stuvia estan en línea:
Garantiza la calidad de los comentarios
Compradores de Stuvia evaluaron más de 700.000 resúmenes. Así estas seguro que compras los mejores documentos!
Compra fácil y rápido
Puedes pagar rápidamente y en una vez con iDeal, tarjeta de crédito o con tu crédito de Stuvia. Sin tener que hacerte miembro.
Enfócate en lo más importante
Tus compañeros escriben los resúmenes. Por eso tienes la seguridad que tienes un resumen actual y confiable. Así llegas a la conclusión rapidamente!
Preguntas frecuentes
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
100% de satisfacción garantizada: ¿Cómo funciona?
Nuestra garantía de satisfacción le asegura que siempre encontrará un documento de estudio a tu medida. Tu rellenas un formulario y nuestro equipo de atención al cliente se encarga del resto.
Who am I buying this summary from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller smartzone. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy this summary for $11.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
45,681 summaries were sold in the last 30 days
Founded in 2010, the go-to place to buy summaries for 14 years now
