If an attribute B is functionally dependent on A, A must be asingle attribute. That is, we cannothave an attribute B functionally dependent on a collection of attributes.

You are watching: A ____ is any key that uniquely identifies each row.


Depending on the sophistication of the application developmentsoftware, nulls can create problems when functions such as COUNT, AVERAGE, andSUM are used.


The relational database model enables you to view data ____ rather than ____.

a.

relationally, hierarchically

c.

physically, logically

b.

hierarchically, relationally


The relational model’s creator, E. F. Codd, used the term relationas a synonym for ____.

a.

index

c.

table

b.

key

d.

relationship


A(n) ____ is perceived as a two-dimensional structure composed ofrows and columns.

a.

table

c.

attribute

b.

rowset

d.

intersection


Date attributes contain calendar dates stored in a special formatknown as the ____ date format.

a.

Epoch

c.

Julian

b.

Calendar

d.

logical


____ data can have only a true or false (yes or no) condition.

a.

Logical

c.

Date

b.

Character

d.

Numeric


In the relational model, ____ are important because they are usedto ensure that each row in a table is uniquely identifiable

a.relations

c.indexes

b.primary keys

d.logical structures


In the context of a database table, the statement “A ____ B”indicates that if you know the value of attribute A, you can look up the valueof attribute B.

a.contains

c.owns

b.is related to

d.determines


The attribute B is ____ the attribute A if each value in column Adetermines one and only one value in column B.

a.logically dependent on

c.determined by

b.owned by

d.functionally dependent on


Any attribute that is part of a key is known as a ____.

a.

key attribute

c.

key determiner

b.

logical attribute

d.

selector


If the attribute (B) is functionally dependent on a composite key(A) but not on any subset of that composite key, the attribute (B) is_____ (A).

a.strongly dependent on

c.fully functionally dependent on

b.weakly dependent on

d.a strong identifier of


A ____ is any key that uniquely identifies each row.

a.

superkey

c.

selective

b.

special

d.

candidate


A ____ is a textual representation of the database tables whereeach table is listed by its name followed by the list of its attributes inparentheses.

a.relational dictionary

c.relational scema

b.logical schema

d.data dictionary


In the following table description, ____ is the primary key.

PRODUCT (PROD_CODE, PROD_DESCRIPT, PROD_PRICE,PROD_ON_HAND, VEND_CODE)

a.PROD_DESCRIPT

c.PROD_PRICE

b.PROD_CODE

d.PROD_ON_HAND


____ means that if the foreign key contains a value, that valuerefers to an existing valid tuple (row) in another relation.

a.referential integrity

c.functional dependence

b.entity integrity

d.relational integrity


A ____ key is defined as a key that is used strictly for dataretrieval purposes.

a.lookup

c.candidate

b.foreign

d.secondary


All primary key entries are unique, and no part of a primary keymay be ____.

a.

zero

c.

null

b.

a foreign key

d.

a candidate key


A CUSTOMER table’s primary key is CUS_CODE. The CUSTOMER primarykey column has no null entries, and all entries are unique. This is an exampleof ____.

a.referential integrity

c.functional dependence

b.entity integrity

d.relational integrity


The ____ constraint can be placed on a column to ensure that everyrow in the table has a value for that column.

a.HAS VALUE

c.MUST HAVE VALUE

b.NOT NULL

d.NOT EMPTY


To be considered minimally relational, the DBMS must support thekey relational operators ____, PROJECT, and JOIN.

a.INTERSECT

c.DIFFERENCE

b.UNION

d.SELECT


____ combines all rows from two tables, excluding duplicate rows.

a.

INTERSECT

c.

DIFFERENCE

b.

UNION

d.

SELECT


____, also known as RESTRICT, yields values for all rows found ina table that satisfy a given condition.

a.

INTERSECT

c.

DIFFERENCE

b.

UNION

d.

SELECT


A(n) ____ join links tables by selecting only the rows with commonvalues in their common attribute(s).

a.

equal

c.

foreign

b.

unique

d.

natural


In a(n) ____ of A and B, the matched pairs would be retained andany unmatched values from table A would also be included in the result set.

a.equijoin

b.natural join

c.left outer join

d.right outer join


A ____ contains at least all of the attribute names andcharacteristics for each table in the system.

a.

data dictionary

c.

logical schema

b.

relational schema

d.

join


The ____ is actually a system-created database whose tables storethe user/designer-created database characteristics and contents.

a.meta dictionary

c.data dictionary

b.schema

d.system catalog


In a database context, the word ____ indicates the use ofthe same attribute name to label different attributes.

a.

redundancy

c.

duplicate

b.

homonym

d.

synonym


In a database context, a(n) ____ indicates the use ofdifferent names to describe the same attribute.

a.

entity

c.

synonym

b.

duplicate

d.

homonym


The ____ relationship exists but should be rare in any relationaldatabase design.

a.

1:1

c.

M:M:N

b.

1:M

d.

M:N


Since it is used to link the tables that originally were relatedin a M:N relationship, the composite entity structure includes—as foreignkeys—at least the ____ keys of the tables that are to be linked.

a.composite

c.primary

b.super

d.unique


A(n) ____ is an ordered arrangement of keys and pointers.

a.

table

c.

relationship

b.

superkey

d.

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index


When you define a table’s primary key, the DBMS automaticallycreates a(n) ____ index on the primary key column(s) you declared.