Multiple choices – Data integrity and normalization
1. In 3NF, which form of dependency is removed?
a. Functional b. Non-functional c. Associative d. Transitive
2. In relational database, table is also called:
a. Tuple b. Relation c. File d. Schema
3. In 3NF, a non-key attribute must not depend on a:
a. Non-key attribute b. Key attribute c. Composite key
4. Different attributes in two different tables having same name are referred to as:
a. Synonym b. Homonym c. Acronym d. Mutually exclusive
5. Every relation must have:
a. Primary key b. Candidate key c. Secondary key d. Mutually exclusiveness
6. The entity integrity rule states that:
a. No primary key attribute can be null b. Each entity must have a primary key c. primary key must have only one attribute d. None
7. A rule that states that each foreign key value must match a primary key value in the other relation is called:
a. Referential integrity constraint b. Key match rule c. Entity key group rule d. Foreign/ primary match rule
8. Two or more attributes having different names but same meaning are called:
a. Homonyms. b. Aliases c. Synonyms d. Alternate attributes
9. A constraint between two attributes is called a(n):
a. Functional Dependency. b. attribute dependency. c. functional dependency. d. Functional relation constraint,
10. The attribute on the left-hand side of the arrow in a functional dependency is:
a. Candidate key b. Determinant c. Foreign key d. primary key
11. The goal of normalization is to:
a. Get stable data structure b. increase number of relation c. increase redundancy d. none
12. A relation is in 2NF if it is in 1NF and all its non-key attributes are:
a. Dependent on part of the primary key b. Dependent on the entire primary key c. Independent of the primary key d. Independent of any other relation
13. In 2NF, which form of dependency is removed?
a. Functional b. Partial c. associative d. transitive
14. Which of the following are anomalies that can be caused by redundancy in tables?
a. Insertion b. Deletion c. Modification d. All
15. A functional dependency between two or more non-key attributes is called:
a. Partial functional dependency b. partial non-key dependency c. Transitive dependency d. None
16. Which of the following anomalies result from a transitive dependency?
a. Insertion b. Modification c. Deletion d. All
17. A relation is in third normal form if it is in second normal form and:
a. Dependent on part of the key b. Dependent on all of the key c. Independent of the key d. Has no transitive dependencies
18. A relation that contains minimal redundancy and allows easy use is called:
a. Clean b. Simple c. Complex d. Well-structured.
19. The 1NF describes the tabular format in which:
a. All the key attributes are defined b. No repeating groups in the table c. all attributes are dependent on primary key d. All
Answers
1. D 2. B 3. A 4. B 5. A 6. A
7. a 8. c 9. c 10. b 11. a 12. b
13. b 14. d 15. c 16. d 17. d 18. d
19. d
Fill in the blanks
1. Entity integrity constraint states that the ……………… cannot not be null.
2. ………………….key must refer to the primary key in another table or it must be null.
3. Normalization is a proc4ess to convert ……..structures in simple and stable structures.
4. A …………….. Is a partial relationship between attributes of an entity?
5. During the first normal form,………. Groups are removed.
6. To be in 2NF, a relation must be in …………….
7. In 2NF, …………. Dependency is removed.
8. In 3NF, no……………….. Dependency exists.
9. When a new record is added in relation, it may cause……………………… anomaly.
10. Referential integrity is a constraint on…………………… key value.
11. A(n)………………… exists when one or more non-key attributes are functionally dependent on part of the primary key.
Answers
1. Primary key 2. Foreign key 3. Complex 4. Functional dependency 5. Repeating 6. 1NF 7. Partial dependency 8. Transitive dependency 9. Insertion 10. Foreign 11. Partial functional dependency
True/ False
1. Normalization converts complex data structure in simple data structure.
2. A relation is decomposed to covert it from 1NF to 2NF.
3. The primary key cannot be a composite key.
4. In 2NF, every non-key attribute must depend on the key attribute.
5. A relationship involving three relations is known as a ternary relationship
6. A database anomaly leads the database on to an inconsistent state.
7. Partial dependencies are removed in 3NF.
8. A relation may have multiple primary keys.
9. The database is normalized to avoid certain database anomalies.
10. In relational database, no relation can exists in isolation.
Answers
1. T 2. T 3. T 4. T 5. T
6. T 7. F 8. T 9. T 10. T