Quiz Discussion

The most commonly used operation in relational algebra for projecting a set of tuple from a relation is

• 1]

  Join

• 2]

  Projection

• 3]

  Select

• 4]

  Union

_____ operator is used for appending two strings.

• 1]

  &

• 2]

  %

• 3]

  ||

• 4]

  _

A relational database consists of a collection of

• 1]

  Tables

• 2]

  Fields

• 3]

  Records

• 4]

  Keys

The tuples of the relations can be of ________ order.

• 1]

  Any

• 2]

  Same

• 3]

  Sorted

• 4]

  Constant

The term attribute refers to a ___________ of a table.

• 1]

  Record

• 2]

  Column

• 3]

  Tuple

• 4]

  Key

SELECT instructor.*
FROM instructor, teaches
WHERE instructor.ID= teaches.ID;

This query does which of the following operation?

• 1]

  All attributes of instructor and teaches are selected

• 2]

  All attributes of instructor are selected on the given condition

• 3]

  All attributes of teaches are selected on given condition

• 4]

  Only the some attributes from instructed and teaches are selected

A domain is atomic if elements of the domain are considered to be ____________ units.

• 1]

  Different

• 2]

  Indivisbile

• 3]

  Constant

• 4]

  Divisible

The ________ clause is used to list the attributes desired in the result of a query.

• 1]

  Where

• 2]

  Select

• 3]

  From

• 4]

  Distinct

The _______ operator takes the results of two queries and returns only rows that appear in both result sets.

• 1]

  Union

• 2]

  Intersect

• 3]

  Difference

• 4]

  Projection

Using which language can a user request information from a database?

• 1]

  Query

• 2]

  Relational

• 3]

  Structural

• 4]

  Compiler