Deck 2: The Relational : Introduction, QBE, and Relational Algebra

Question 1

A column whose value uniquely identifies a given row in the table is the secondary key.​

Answer 1

False

Question 2

The ____ key of a table is the column or collection of columns that uniquely identifies a given row in that table.​

A) ​primary
B) ​secondary
C) ​foreign
D) ​minor

Answer 2

A

Question 3

The concept of grouping means that statistics will be calculated for individual records.​

Answer 3

False

Question 4

QBE is a visual approach to writing queries.​

Question 5

The attributes of an entity become the fields or columns in a table.​

Question 6

An unnormalized relation is a table that has more than one row.​

Question 7

​Based on the statement below,which of the following is the primary key? Rep (RepNum,LastName,FirstName,Street,City,State,PostalCode Commission,Rate)

A) ​RepNum
B) ​LastName
C) ​FirstName
D) ​State

Question 8

​The comparison operators are also known as relational operators.

Question 9

In an AND criterion,the overall criterion is true if either of the individual criteria is true.​

Question 10

When duplicate column names exist in a database and you need to indicate the column to which you are referring,____.​

A) ​do not use these two tables together
B) ​do not use the column names in the same statement
C) ​write both the table name and the column name, separated by a period
D) ​write the table name only

Question 11

A relational database is a collection of relations.

Question 12

In a relation,the order of the columns is important.

Question 13

Access automatically adds double quotation marks around values in the design grid that are formatted as Short Text fields when you run the query or move the insertion point to another cell in the design grid.​

Question 14

Each column in a table should have a unique name,and entries in each column should all "match" this column name.​

Question 15

In a relation,the order of rows is important.​

Question 16

​A query is a question represented in a way that the DBMS can recognize and process.

Question 17

Rows are also called ____.​

A) ​fields
B) ​columns
C) ​tuples
D) ​attributes

Question 18

A relation is a(n)____.​

A) ​attribute
B) ​column
C) ​field
D) ​table

Question 19

A relational database handles entities,attributes,and relationships by storing each entity in its own table.​

Question 20

The comparison operators are +,*,%,and /.​

Question 21

Which operation will allow you to extract data from more than one table?​

A) ​Select
B) ​Merge
C) ​Project
D) ​Join

Question 22

If you are sorting records by more than one field,the more important field is called the ____.​

A) ​primary sort key
B) ​secondary sort key
C) ​maximum sort key
D) ​minor sort key

Question 23

When a structure satisfies all the properties of a relation except for the first item-in other words,some entries contain repeating groups and thus are not single-valued-it is referred to as a(n)____________________.​

Question 24

The ____ command within relational algebra includes the word OVER followed by a list of the columns to be included.​

A) ​DELETE
B) ​PROJECT
C) ​INTERSECT
D) ​UNION

Question 25

The compound criteria (conditions)are created by using ____.​

A) ​AND, OR
B) ​AND, NOR
C) ​OR, NOT
D) ​NOT, ONLY

Question 26

A query that changes data is a(n)____ query.​

A) ​addition
B) ​update
C) ​update
D) ​select

Question 27

You can restrict the output from a join to include only certain columns by using the ____ command.​

A) ​DELETE
B) ​UNION
C) ​PROJECT
D) ​INTERSECT

Question 28

The product of two tables is also called the ____ product.​

A) ​Cartesian
B) ​aggregate
C) ​Cathode
D) ​exponential

Question 29

A(n)____________________ database is a collection of tables.​

Question 30

Based on the Customer table below,which command lists all information from the table concerning customer 260?​ CustomerNum CustomerName Street City State PostalCode
126 Toys Galore 28 Laketon St. Fulton CA 90085
260 Brookings Direct 452 Columbus Dr. Grove CA 90092

A) ​SELECT Customer 260 GIVING Answer
B) ​SELECT Customer WHERE CustomerNum=260 GIVING Answer
C) ​SELECT Customer WHERE Customernum='260' GIVING Answer
D) ​SELECT Customer WHERE CustomerName='260' GIVING Answer

Question 31

Two tables are considered to be ____ compatible if they have the same number of columns and their corresponding columns represent the same type of data.​

A) ​union
B) ​intersection
C) ​difference
D) ​product

Question 32

Count,Sum,Avg,Max,and Min are a few of the built-in statistics or ____ functions that can be used in a query.​

A) ​accumulated
B) ​allowed
C) ​primary
D) ​aggregate

Question 33

Multiple entries in tables are often called ____________________.​

Question 34

Columns in a table are often called ____________________.​

Question 35

The relationships between tables are handled through ____________________ columns.​

Question 36

The ____ command within relational algebra takes a vertical subset of a table.​

A) ​SELECT
B) ​DELETE
C) ​PROGRAM
D) ​PROJECT

Question 37

Using the product operator,if table A has 4 rows and table B has 4 rows,the number of rows in the product of these two tables is ____.​

A) ​4
B) ​8
C) ​16
D) ​256

Question 38

The ____ operation is performed by the SUBTRACT command in relational algebra.​

A) ​union
B) ​difference
C) ​product
D) ​intersection

Question 39

The ____ operator is used to concatenate every row in the first table with every row in the second table.​

A) ​union
B) ​difference
C) ​product
D) ​intersection

Question 40

A ____ query creates a new table using the query results.​

A) ​new-table
B) ​make-table
C) ​create-table
D) ​merge-table

Question 41

Explain what relational algebra is and how it is used.​

Question 42

​Conditions that data must satisfy are called ____________________.

Question 43

​A(n)____________________ field is a field that is the result of a calculation using one or more existing fields.

Question 44

The field on which records are sorted is called the ____________________.​

Question 45

____________________ is a theoretical way of manipulating a relational database.

Question 46

​Provide a definition for the term relation.

Question 47

​What is the difference between an AND criterion and an OR criterion? How is each criterion created in QBE?

Question 48

List at least six of the aggregate functions available in Access.Explain how to use any of these functions in a query.​

Question 49

To list the records in a query's results in a particular order,you need to ____________________ the records.​

Question 50

Discuss the difference between the major sort key and the minor sort key.​