Download CS304 Database Concepts

SE305
Database System Technology
25/09/2014
Quiz-1
1. Which information is NOT contained in Data
dictionary?
a) Database schema
b) Integrity constraints
c) Authorization information
d) Index
2. Which level of abstraction does describe how a
record is stored?
a) Physical Level
b) Logical Level
c) Database Level
d) View Level
3. Which option is NOT a data model?
a) Network model
b) Entity-Relationship data model
c) Object-relational model
d) Semi-Object model
4. Which statement about relational model is FALSE?
a) Collection of tables
b) Flat, “atomic” values
c) Semi-structured
d) Can contain null values
5. If K is chosen as the principal means of
identifying tuples within a relation, then K is?
a) Superkey
b) Candidate Key
c) Primary Key
d) Foreign key
6. Which language is NOT a “Pure” language?
a) Relational algebra
b) Tuple relational calculus
c) Domain relational calculus
d) SQL
7. How many basic operators in Relational
Algebra?
a) 5
b) 6
c) 7
d) 8
8. What’s the value of 𝑟 ÷ 𝑠? Ans:A
9. Which SQL statement does describe selecting all
person whose salary is higher than $1,000 from people
relation p?
a) 𝜎𝑠𝑎𝑙𝑎𝑟𝑦≥1000∧𝑑𝑒𝑝𝑡="𝐶𝑜𝑚𝑝." (𝑝)
b) Π𝑠𝑎𝑙𝑎𝑟𝑦 𝜎𝑠𝑎𝑙𝑎𝑟𝑦≥1000 (𝑝)
c) 𝜎𝑠𝑎𝑙𝑎𝑟𝑦≥1000 (𝑝)
d) 𝜎𝑠𝑎𝑙𝑎𝑟𝑦≥1000 Π𝑠𝑎𝑙𝑎𝑟𝑦 (𝑝)
10. Which equation is NOT correct? (R(A,B,C,D) S(E,B,D)
for option b)
a) 𝑟 ∩ 𝑠 = 𝑟 − (𝑠 − 𝑟)
b) r ⋈ 𝑠 = Π 𝑟.𝐴,𝑟.𝐵,𝑟.𝐶,𝑟.𝐷,𝑠.𝐸 𝜎𝑟.𝐵=𝑠.𝐵∧𝑟.𝐷=𝑠.𝐷 𝑟 × 𝑠
c) 𝑟 ÷ 𝑠 = Π𝑅−𝑆 𝑟 − Π𝑅−𝑆
d) 𝑟 ∩ 𝑠 = 𝑠 ∩ 𝑟
Π𝑅−𝑆 𝑟 × 𝑠 − Π𝑅−𝑆,𝑆 𝑟