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

The ______ clause allows us to select only those rows in the result relation of the ____ clause that satisfy a specified predicate.

• 1]

  Where, from

• 2]

  From, select

• 3]

  Select, from

• 4]

  From, where

The_____ operation allows the combining of two relations by merging pairs of tuples, one from each relation, into a single tuple.

• 1]

  Select

• 2]

  Join

• 3]

  Union

• 4]

  Intersection

The tuples of the relations can be of ________ order.

• 1]

  Any

• 2]

  Same

• 3]

  Sorted

• 4]

  Constant

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.

• 1]

  Instance, Schema

• 2]

  Relation, Schema

• 3]

  Relation, Domain

• 4]

  Schema, Instance

A relational database consists of a collection of

• 1]

  Tables

• 2]

  Fields

• 3]

  Records

• 4]

  Keys

SELECT *
FROM instructor
ORDER BY salary ____, name ___;

To display the salary from greater to smaller and name in ascending order which of the following options should be used?

• 1]

  Ascending, Descending

• 2]

  Asc, Desc

• 3]

  Desc, Asc

• 4]

  Descending, Ascending

Student(ID, name, dept name, tot_cred)
In this query which attributes form the primary key?

• 1]

  Name

• 2]

  Dept

• 3]

  Tot_cred

• 4]

  ID

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

The _______operation performs a set union of two “similarly structured” tables

• 1]

  Union

• 2]

  Join

• 3]

  Product

• 4]

  Intersect