Database Management System
The Relational Database Model
Q.

Which of the following best describes the query?


{t | Э s ε instructor (t[name] = s[name]
∧ Э u ε department (u[dept name] = s[dept name]
∧ u[building] = “Watson”))}

 
A.  Finds the names of all instructors whose department is in the Watson building B.  Finds the names of all department is in the Watson building C.  Finds the name of the dapartment whose instructor and building is Watson D.  Returns the building name of all the departments
Similar Questions
1. Relational calculus is a
A.  Procedural language. B.  Non- Procedural language. C.  Data definition language. D.  High level language.
2. Cartesian product in relational algebra is
A.  a Unary operator. B.  a Binary operator. C.  a Ternary operator. D.  not defined.
3. In a relational model, relations are termed as
A.  Tuples B.  Attributes C.  Tables D.  Rows
4. An entity set that does not have sufficient attributes to form a primary key is a
A.  strong entity set. B.  weak entity set. C.  simple entity set. D.  primary entity set.
5. A relational database developer refers to a record as
A.  a criteria. B.  a relation. C.  a tuple. D.  an attribute.
6. The relational model feature is that there
A.  is no need for primary key data. B.  is much more data independence than some other database models. C.  are explicit relationships among records. D.  are tables with many dimensions.
7. Relational Algebra is
A.  Data Definition Language . B.  Meta Language C.  Procedural query Language D.  None of the above
8. Which of the following operation is used if we are interested in only certain columns of a table?
A.  PROJECTION B.  SELECTION C.  UNION D.  JOIN
9. . Which of the following operations need the participating relations to be union compatible?
A.  UNION B.  INTERSECTION C.  DIFFERENCEqq D.  All of the above
10. Which of the operations constitute a basic set of operations for manipulating relational data?
A.  Predicate calculus B.  Relational calculus C.  Relational algebra D.  None of the above
DATABASE MANAGEMENT SYSTEM TOPICS