Deck 4: Database Design Using Normalization

Question 1

To limit the number of rows retrieved from a table,use the SQL TOP keyword.

Answer 1

True

Question 2

To determine the number and type of columns in a table,use the SQL construct COUNT(*).

Answer 2

False

Question 3

The first step in assessing table structure is to count rows and examine columns.

Answer 3

True

Question 4

Normalization eliminates modification anomalies and data duplication.

Question 5

When examining data values as a part of assessing table structure,you should try to determine the table's primary key.

Question 6

Relations are sometimes left unnormalized to improve performance.

Question 7

When examining data values as a part of assessing table structure,you should try to determine two types of dependencies: functional dependencies and functional dependencies.

Question 8

When examining data values as a part of assessing table structure,there is no need to try to determine foreign keys.

Question 9

The third step in assessing table structure is to check the validity of presumed referential integrity constraints.

Question 10

When examining data values as a part of assessing table structure,there is no need to try to determine candidate keys other than the table's primary key.

Question 11

When examining data values as a part of assessing table structure,you should try to determine three types of keys: the primary key,any candidate keys and any foreign keys.

Question 12

To count the number of rows in a table,use the SQL construct COUNT(ROWS).

Question 13

The second step in assessing table structure is to examine data values and determine dependencies and keys.

Question 14

The presence of one or more foreign keys in a relation means that we cannot eliminate duplicated data in that table.

Question 15

When examining data values as a part of assessing table structure,you should try to determine multivalued dependencies.

Question 16

Normalization requires applications to use more complex SQL since they will need to write subqueries and joins to recombine data stored in separate relations.

Question 17

When you are given a set of tables and asked to create a database to store their data,the first step is to assess the tables' structure and content.

Question 18

Database design varies depending on whether you're building an updatable database or a read-only database.

Question 19

When examining data values as a part of assessing table structure,you should try to determine functional dependencies.

Question 20

The elimination of modification anomalies and the reduction of duplicated data are advantages of normalization.

Question 21

SQL statements that can be used to create referential integrity statements for normalized tables are created during the normalization process.

Question 22

Read-only databases are often updated.

Question 23

Normalization is an advantage for a read-only database.

Question 24

The SQL DELETE TABLE statement can be used to remove unneeded tables after the normalized tables are created and populated.

Question 25

The standard sales order/line item pattern is a classic example of unneeded normalization.

Question 26

A defining requirement for BCNF is that every determinant must be a candidate key.

Question 27

Multivalued dependencies show up under a different name as the multivalued,multicolumn problem.

Question 28

The SQL INSERT statement can be used to populate normalized tables.

Question 29

Denormalization is the process of joining previously normalized tables back together.

Question 30

Design guidelines and priorities are the same whether you're working with an updatable database or a read-only database.

Question 31

To eliminate multivalued dependencies,normalize your tables so that they are all in BCNF.

Question 32

Multivalued dependencies create anomalies so serious that multivalued dependencies must always be eliminated.

Question 33

The multivalued,multicolumn problem occurs when a set of columns are used to store data that should actually be in one column.

Question 34

Creating a read-only database is a job often given to beginning database professionals.

Question 35

Read-only databases seldom use more than one copy of a set of same data.

Question 36

Denormalization is simple-join the data together and store it in a table.

Question 37

Read-only databases often use several copies of a set of the same data,where each copy is modified for a specific use.

Question 38

Denormalization reduces the complexity of the SQL statements needed in an application to read required data.

Question 39

Relations in BCNF have no modification anomalies in regard to functional dependencies.

Question 40

Writing SQL subqueries and joins against normalized tables is simple compared to the code that must be written to handle anomalies from multivalued dependencies.

Question 41

One situation created by the multivalued,multicolumn problem is that the maximum number of data values for an attribute is limited.

Question 42

During the second step of assessing table structure,you are trying to determine ________.

A)multivalued dependencies
B)functional dependencies
C)foreign keys
D)A and B
E)A,B,and C

Question 43

When you are creating a database from existing data,you will have only minor problems with inconsistent values.

Question 44

The problem of misspelled data entries is an entirely different problem than the inconsistent values problem.

Question 45

When you are given a set of tables and asked to create a database to store their data,the first step is to ________.

A)assess the existing tables' structure and content
B)design the database structure
C)create one or more new tables
D)move the data into the new database
E)design the applications that will use the database

Question 46

The first step in assessing table structure includes ________.

A)counting rows
B)examining columns
C)examining data values
D)A and B
E)B and C

Question 47

The second step in assessing table structure includes ________.

A)counting rows
B)examining columns
C)examining data values
D)A and B
E)B and C

Question 48

A null value in a column may indicate that there is no appropriate value for that attribute.

Question 49

You are creating a BOAT table using existing data from multiple sources,and you find that you have "power boat blue","boat,power,blue" and "blue power boat" as data values for the same column.This is an example of the inconsistent values problem.

Question 50

If you have a table with a set of columns named "Child01","Child02" and "Child03",the table has the multivalued,multicolumn problem.

Question 51

Null values are a problem because they are ambiguous.

Question 52

If you see a column name Notes,it is likely that this is a general-purpose remarks column.

Question 53

A null value in a column may indicate that there is an appropriate value for that attribute,and although the value is known no one has entered the value into the database.

Question 54

The SQL IS NULL keyword can be used to count the number of nulls in a column.

Question 55

A missing value is called a null value.

Question 56

An inconsistent values problem is created when different users have coded the same data entries differently.

Question 57

The problem with a general-purpose remarks column is that the data it contains are likely to be verbal,inconsistent and stored in a verbose manner.

Question 58

General-purpose remarks columns rarely contain important data.

Question 59

A null value in a column may indicate that there is an appropriate value for that attribute,but it is unknown.

Question 60

Most DBMS products will let you define a primary key on a column that contains null values.

Question 61

The defining characteristic of BCNF is that a table is in BCNF if ________.

A)all rows are unique
B)all columns are consistent
C)the primary key is a candidate key
D)all determinants are candidate keys
E)all candidate keys are determinants

Question 62

A form of multivalued dependency is found in ________.

A)the multivalued,multicolumn problem
B)the inconsistent values problem
C)the missing values problem
D)the general-purpose remarks column problem
E)None of the above is correct.

Question 63

A classic example of unneeded normalization is when we are dealing with ________.

A)ZIP codes
B)sales orders and line items
C)association patterns
D)multivalued dependencies
E)general purpose remarks columns

Question 64

________ is the process of joining two or more tables and storing the result as a single table.

A)Querying
B)Normalization
C)Denormalization
D)A and B
E)B and C

Question 65

When a table is created using existing data from multiple sources,you are likely to find that the different sources code data in slightly different ways.This is an example of ________.

A)the multivalued,multicolumn problem
B)the inconsistent values problem
C)the missing values problem
D)the general-purpose remarks column problem
E)None of the above is correct.

Question 66

To count the number of rows in a table,use the SQL construct ________.

A)SELECT *
B)SELECT TOP n *
C)SELECT COUNT(TOP n)
D)SELECT COUNT(*)
E)SELECT COUNT *

Question 67

The advantages of normalization include ________.

A)the elimination of modification anomalies
B)the elimination of duplicated data
C)more complex SQL for multitable subqueries and joins
D)A and B
E)A,B,and C

Question 68

The presence of one or more foreign keys in a relation prevents ________.

A)the elimination of modification anomalies
B)the elimination of duplicated data
C)more complex SQL for multitable subqueries and joins
D)A and B
E)A,B,and C

Question 69

The SQL keyword TOP ________.

A)limits the number of columns retrieved from a table
B)limits the number of rows retrieved from a table
C)limits the number of tables retrieved from a database
D)A and C
E)B and C

Question 70

An advantage of denormalization is ________.

A)faster updating
B)faster querying
C)less complex SQL in application code
D)A and B
E)B and C

Question 71

Unlike the anomalies from functional dependencies,the anomalies from ________ are so serious that they should always be eliminated.

A)ZIP codes
B)sales orders and line items
C)association patterns
D)multivalued dependencies
E)general purpose remarks columns

Question 72

You have been given two tables,CUSTOMER and SALE.You want to check the referential integrity constraint: SALE.CustomerNumber must exist in CUSTOMER.CustomerNumber
You run the following SQL query:
SELECT CustomerNumber
FROM SALE
WHERE CustomerNumber NOT IN
(SELECT CustomerNumber
FROM SALE,CUSTOMER
WHERE SALE.CustomerNumber = CUSTOMER.CustomerNumber);
What is shown in the results of this query?

A)All values of CustomerNumber that match the constraint.
B)All values of CustomerNumber that violate the constraint.
C)All values of CustomerNumber where
SALE.CustomerNumber = CUSTOMER.CustomerNumber.
D)A and C
E)B and C

Question 73

The disadvantages of normalization include ________.

A)the elimination of modification anomalies
B)the elimination of duplicated data
C)more complex SQL for multitable subqueries and joins
D)A and B
E)A,B,and C

Question 74

During the second step of assessing table structure,you are trying to determine ________.

A)primary keys
B)candidate keys
C)foreign keys
D)A and B
E)A,B,and C

Question 75

Read-only databases are used for ________.

A)updating
B)querying
C)reporting
D)A and B
E)B and C

Question 76

To limit the number of rows retrieved from a table,use the SQL construct ________.

A)SELECT *
B)SELECT TOP n *
C)SELECT COUNT(TOP n)
D)SELECT COUNT(*)
E)SELECT COUNT *

Question 77

For a number of reasons,________ is not often an advantage for a read-only database.

A)updating
B)normalization
C)denormalization
D)A and B
E)B and C

Question 78

The SQL function COUNT ________.

A)counts the number of columns in a table
B)counts the number of rows in a table
C)counts the number of tables in a database
D)A and C
E)B and C

Question 79

A table designed to store PhoneNumber01,PhoneNumber02 and PhoneNumber03 contains ________.

A)the multivalued,multicolumn problem
B)the inconsistent values problem
C)the missing values problem
D)the general-purpose remarks column problem
E)None of the above is correct.

Question 80

Anomalies caused by functional dependencies can be eliminated by putting tables into ________.

A)1NF
B)2NF
C)3NF
D)BCNF
E)4NF