Name: 
 

RelationalModel


Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
 

1. 
Nulls, if used improperly, can create problems because they can represent:
a.
An unknown attribute value.
b.
A known, but missing, attribute value.
c.
A "not applicable" condition.
d.
All of the above
e.
None of the above
 

2. 
The entity integrity rule requires that
a.
all entries are unique.
b.
a part of the key may be null.
c.
foreign key values do not reference primary key values.
d.
duplicate object values are allowed.
 

3. 
The referential integrity rule requires that
a.
every null foreign key value must reference an existing primary key value.
b.
it makes it possible for an attribute to have a corresponding value.
c.
every non-null foreign key value must reference an existing primary key value.
d.
it makes it possible to delete a row in one table whose primary key does not have a matching foreign key value in another table.
 

4. 
Data are classified according to their format and function and consist of
a.
Numeric, Date, and Alphanumeric.
b.
Numeric, Date, Alphanumeric, and Logical
c.
Numeric, Character, and Date
d.
Numeric, Character, Date, and Logical
 

5. 
Each table is perceived as
a.
a flat structure.
b.
a two-dimensional structure.
c.
a linked structure.
d.
none of the above
 

6. 
The word Relation is also known as
a.
datafile.
b.
data index.
c.
dataset.
d.
data query.
 

7. 
The logical view of the relational database is facilitated by
a.
the wizard.
b.
the use of tables.
c.
the creation of queries using the wizard.
d.
the creation of data relationships based on a construct known as table.
 

8. 
Each table must have
a.
a primary key.
b.
a secondary key.
c.
a foreign key.
d.
a logical key.
 

9. 
The key's role is based on a concept known as
a.
consistency.
b.
availability.
c.
determination.
d.
uniqueness.
 

10. 
A superkey is any key that uniquely identifies each
a.
entity in a table.
b.
object in a table.
c.
table.
d.
structure in a table.
 

11. 
A primary key
a.
must be defined in every table.
b.
is always the first field in each table.
c.
must be numeric.
d.
must be unique.
 

12. 
A table can be logically connected to another table by defining a
a.
hyperlink.
b.
common field.
c.
primary key.
d.
foreign key.
 

13. 
A Relational operator that yields values from all rows in a table is known as a
a.
difference.
b.
product.
c.
select.
d.
project.
 

14. 
A Relational operator that yields all values from selected attributes is known as a
a.
difference.
b.
product.
c.
select.
d.
project.
e.
join.
 

15. 
A Relational operator that allows for the combination of information from two or more tables is known as a
a.
select.
b.
project.
c.
product.
d.
difference.
e.
join.
 

16. 
In a relationship, when a primary key from one table is also defined in a second table, the field is referred as a ____________in the second table.
a.
combined key
b.
redundant field
c.
primary key
d.
foreign key
 

17. 
A Relational operator that yields all possible pairs of rows from two tables is known as a
a.
union.
b.
intersect.
c.
difference.
d.
product.
e.
project.
 

18. 
A primary key that consists of more than one field is called a
a.
foreign key.
b.
secondary key.
c.
group key.
d.
all of the above
e.
none of the above
 

19. 
A Relational operator that yields all rows in one table that are not found in the other table is a
a.
union.
b.
intersect.
c.
difference.
d.
product.
e.
project.
 

20. 
The field size of a Date/Time type of field is
a.
8 bytes.
b.
16 bytes.
c.
dependent on the format selected.
d.
user defined.
 

21. 
A field that consists of integer values that are controlled by Access is a(n) _________ type field.
a.
Date/Time
b.
Yes/No
c.
Memo
d.
AutoNumber
 

22. 
When creating a table, what happens when you do not assign a field as primary key?
a.
The table will not have a primary or foreign key.
b.
The program will select one of your fields as primary key.
c.
The table will not have a primary key but it will have a foreign key.
d.
The program will create an ID field and assign it as primary key.
 

23. 
A set of allowable operations for a dates field might be:
a.
compare two dates
b.
find the difference in days between two dates
c.
create a date by adding or subtracting a number of days from a given date
d.
convert a date from its internal representation to a different presentation format
e.
all of the above
 

24. 
In general terms the _____________ key is an attribute (or combination of attributes) that uniquely identifies any given entity.
a.
indexed
b.
primary
c.
foreign
d.
redundant
 

25. 
In the context of a database table, the statement "A determines B" indicates that
a.
knowing the value of attribute A you can not look up the value of attribute B.
b.
you do not need to know the value of attribute A in order to look up the value of attribute B.
c.
knowing the value of attribute B you can look up the value of attribute A.
d.
knowing the value of attribute A you can look up the value of attribute B.
 

26. 
A _____________ key is any key that identifies each entity uniquely.  It functionally determines all of the entity's attributes.
a.
superkey
b.
primary
c.
foreign
d.
combined
 

27. 
It might take more than a single attribute to define functional dependence; that is, a key may be composed of more than one attribute.  A multi-attribute key is known as a _____ key.
a.
primary
b.
super
c.
composite
d.
foreign
 

28. 
Within a table, the primary key must be unique so that it will identify each row.  When this is the case, the table is said to exhibit ___________.
a.
referential integrity.
b.
entity integrity.
c.
enforced integrity.
d.
all of the above
 

29. 
In a sophisticated application development software, nulls can create problems when using functions such as
a.
count
b.
average
c.
sum
d.
a & c
e.
a b & c
 

30. 
We can describe a link by observing that
a.
a primary key of one table appears again as a primary key in a related table.
b.
a foreign key of one table appears again as a foreign key in a related table.
c.
a primary key of one table appears again as a foreign key in a related table.
d.
a foreign key of one table appears again as a primary key in a related table.
 

31. 
When designing a new database, it is a good idea to
a.
avoid data redundancy.
b.
include redundant fields.
c.
include a common field in all tables.
d.
use composite keys.
 

32. 
If a foreign key contains either matching values or nulls, the table(s) that make use of such a foreign key is/are said to exhibit __________ integrity.
a.
referential
b.
restrictive
c.
secondary
d.
redundant
 

33. 
A ______________ key is defined as a key that is used strictly for data retrieval purposes.
a.
primary
b.
foreign
c.
secondary
d.
data
 

34. 
A _________________ key's effectiveness in narrowing down a search depends on how restrictive it is.
a.
primary
b.
foreign
c.
secondary
d.
search
 

35. 
A superkey that does not contain a subset of attributes that is itself a superkey is called a
a.
candidate key.
b.
primary key.
c.
superkey.
d.
secondary key.
e.
foreign key.
 

36. 
An attribute (or combination of attributes) that uniquely identifies each entity in a table is called
a.
superkey.
b.
candidate key.
c.
primary key.
d.
secondary key.
e.
foreign key.
 

37. 
A candidate key selected to uniquely identify all other attribute values in any given row, and can not have a null value is called a
a.
superkey.
b.
candidate key.
c.
primary key.
d.
secondary key.
e.
foreign key.
 

38. 
An attribute (or combination of attributes) used strictly for data retrieval purposes is called a
a.
superkey.
b.
candidate key.
c.
primary key.
d.
secondary key
e.
foreign key.
 

39. 
An attribute (or combination of attributes) in one table whose values must either match the primary key in another table or be null is called a
a.
superkey.
b.
candidate key.
c.
primary key.
d.
secondary key.
e.
foreign key.
 

40. 
A null value is created or represented by
a.
a zero.
b.
a space.
c.
entering a value.
d.
pressing the Enter key without making a prior entry of any kind.
 

41. 
The link can be described by observing that it is created when
a.
two tables share a common attribute.
b.
two tables share different attributes.
c.
a primary key of one table appears as a foreign key in a related table.
d.
a and b
e.
a and c
 

42. 
A secondary key is used strictly
a.
for data confirmation.
b.
for data retrieval purposes.
c.
for data verification
d.
all of the above
 

43. 
A key that consists of more than one field is called
a.
a foreign key
b.
a composite key
c.
a redundant key
d.
none of the above
 

44. 
A field name can begin with a
a.
period.
b.
dash.
c.
character.
d.
dollar sign.
 

45. 
On a customer table, data retrieval for a specific customer can be facilitated when customer's number, last name, and phone number are used where the
a.
customer's last name is primary key
b.
customer's number is the primary key
c.
the secondary key is a combination of customer's last name and phone number
d.
a & c
e.
b & c
 

46. 
Records in a table are stored on disk in the order they are entered but are displayed in ____________ key sequence.
a.
primary
b.
foreign
c.
composite
d.
redundant
 

47. 
To be considered minimally relational, the Data Base Management System must support the key relational operator(s)
a.
select
b.
project
c.
join
d.
a & c
e.
a b & c
 

48. 
A Relational operator that combines all rows from two tables is considered to be a
a.
union.
b.
intersect.
c.
difference.
d.
product.
e.
project.
 



 
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