30 MOST IMPORTANT MCQ'S FOR RELATIONAL DATABASE MODEL
1. A relational database consists of a collection of
a) Tables
b) Fields
c) Records
d) Keys
2. A ________ in a table represents a relationship among a set of values.
a) Column
b) Key
c) Row
d) Entry
3. The term _______ is used to refer to a row.
a) Attribute
b) Tuple
c) Field
d) Instance
4. The term attribute refers to a ___________ of a table.
a) Record
b) Column
c) Tuple
d) Key
5. For each attribute of a relation, there is a set of permitted values, called the ________ of that attribute.
a) Domain
b) Relation
c) Set
d) Schema
6. Database __________ which is the logical design of the database, and the database _______ which is a snapshot of the data in the database at a given instant in time.
a) Instance, Schema
b) Relation, Schema
c) Relation, Domain
d) Schema, Instance
7. Course(course_id,sec_id,semester)
Here the course_id,sec_id and semester are __________ and course is a _________
a) Relations, Attribute
b) Attributes, Relation
c) Tuple, Relation
d) Tuple, Attributes
8. Department (dept name, building, budget) and Employee (employee_id, name, dept name, salary)
Here the dept_name attribute appears in both the relations. Here using common attributes in relation schema is one way of relating ___________ relations.
a) Attributes of common
b) Tuple of common
c) Tuple of distinct
d) Attributes of distinct
9. A domain is atomic if elements of the domain are considered to be ____________ units.
a) Different
b) Indivisbile
c) Constant
d) Divisible
10. The tuples of the relations can be of ________ order.
a) Any
b) Same
c) Sorted
d) Constant
11. Which one of the following is a set of one or more attributes taken collectively to uniquely identify a record?
a) Candidate key
b) Sub key
c) Super key
d) Foreign key
12. Consider attributes ID, CITY and NAME. Which one of this can be considered as a super key?
a) NAME
b) ID
c) CITY
d) CITY, ID
13. The subset of a super key is a candidate key under what condition?
a) No proper subset is a super key
b) All subsets are super keys
c) Subset is a super key
d) Each subset is a super key
14. A _____ is a property of the entire relation, rather than of the individual tuples in which each tuple is unique.
a) Rows
b) Key
c) Attribute
d) Fields
15. Which one of the following attribute can be taken as a primary key?
a) Name
b) Street
c) Id
d) Department
16. Which one of the following cannot be taken as a primary key?
a) Id
b) Register number
c) Dept_id
d) Street
17. An attribute in a relation is a foreign key if the _______ key from one relation is used as an attribute in that relation.
a) Candidate
b) Primary
c) Super
d) Sub
18. The relation with the attribute which is the primary key is referenced in another relation. The relation which has the attribute as a primary key is called
a) Referential relation
b) Referencing relation
c) Referenced relation
d) Referred relation
19. The ______ is the one in which the primary key of one relation is used as a normal attribute in another relation.
a) Referential relation
b) Referencing relation
c) Referenced relation
d) Referred relation
20. A _________ integrity constraint requires that the values appearing in specified attributes of any tuple in the referencing relation also appear in specified attributes of at least one tuple in the referenced relation.
a) Referential
b) Referencing
c) Specific
d) Primary
21. Using which language can a user request information from a database?
a) Query
b) Relational
c) Structural
d) Compiler
22. Student(ID, name, dept name, tot_cred)
In this query which attributes form the primary key?
a) Name
b) Dept
c) Tot_cred
d) ID
23. Which one of the following is a procedural language?
a) Domain relational calculus
b) Tuple relational calculus
c) Relational algebra
d) Query language
24. The_____ operation allows the combining of two relations by merging pairs of tuples, one from each relation, into a single tuple.
a) Select
b) Join
c) Union
d) Intersection
25. The result which operation contains all pairs of tuples from the two relations, regardless of whether their attribute values match.
a) Join
b) Cartesian product
c) Intersection
d) Set difference
26. The _______operation performs a set union of two “similarly structured” tables
a) Union
b) Join
c) Product
d) Intersect
27. The most commonly used operation in relational algebra for projecting a set of tuple from a relation is
a) Join
b) Projection
c) Select
d) Union
28. The _______ operator takes the results of two queries and returns only rows that appear in both result sets.
a) Union
b) Intersect
c) Difference
d) Projection
29. A ________ is a pictorial depiction of the schema of a database that shows the relations in the database, their attributes, and primary keys and foreign keys.
a) Schema diagram
b) Relational algebra
c) Database diagram
d) Schema flow
30. The _________ provides a set of operations that take one or more relations as input and return a relation as an output.
a) Schematic representation
b) Relational algebra
c) Scheme diagram
d) Relation flow
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