Exercise 2.2.1a
For relation Accounts, the attributes are:
acctNo, type, balance
For relation Customers, the attributes are:
firstName, lastName, idNo, account
Exercise 2.2.1b
For relation Accounts, the tuples are:
(12345, savings, 12000),
(23456, checking, 1000),
(34567, savings, 25)
For relation Customers, the tuples are:
(Robbie, Banks, 901-222, 12345),
(Lena, Hand, 805-333, 12345),
(Lena, Hand, 805-333, 23456)
Exercise 2.2.1c
,For relation Accounts and the first tuple, the components are:
123456 acctNo
savings type
12000 balance
For relation Customers and the first tuple, the components are:
Robbie firstName
Banks lastName
901-222 idNo
12345 account
Exercise 2.2.1d
For relation Accounts, a relation schema is:
Accounts(acctNo, type, balance)
For relation Customers, a relation schema is:
Customers(firstName, lastName, idNo, account)
Exercise 2.2.1e
,An example database schema is:
Accounts (
acctNo,
type,
balance
)
Customers (
firstName,
lastName,
idNo,
account
)
Exercise 2.2.1f
A suitable domain for each attribute:
acctNo Integer
type String
balance Integer
firstName String
lastName String
idNo String (because there is a hyphen we cannot use Integer)
account Integer
, Exercise 2.2.1g
Another equivalent way to present the Account relation:
acctNo balance type
34567 25 savings
23456 1000 checking
12345 12000 savings
Another equivalent way to present the Customers relation:
idNo firstName lastName account
805-333 Lena Hand 23456
805-333 Lena Hand 12345
901-222 Robbie Banks 12345
Exercise 2.2.2
Examples of attributes that are created for primarily serving as keys in a relation:
For relation Accounts, the attributes are:
acctNo, type, balance
For relation Customers, the attributes are:
firstName, lastName, idNo, account
Exercise 2.2.1b
For relation Accounts, the tuples are:
(12345, savings, 12000),
(23456, checking, 1000),
(34567, savings, 25)
For relation Customers, the tuples are:
(Robbie, Banks, 901-222, 12345),
(Lena, Hand, 805-333, 12345),
(Lena, Hand, 805-333, 23456)
Exercise 2.2.1c
,For relation Accounts and the first tuple, the components are:
123456 acctNo
savings type
12000 balance
For relation Customers and the first tuple, the components are:
Robbie firstName
Banks lastName
901-222 idNo
12345 account
Exercise 2.2.1d
For relation Accounts, a relation schema is:
Accounts(acctNo, type, balance)
For relation Customers, a relation schema is:
Customers(firstName, lastName, idNo, account)
Exercise 2.2.1e
,An example database schema is:
Accounts (
acctNo,
type,
balance
)
Customers (
firstName,
lastName,
idNo,
account
)
Exercise 2.2.1f
A suitable domain for each attribute:
acctNo Integer
type String
balance Integer
firstName String
lastName String
idNo String (because there is a hyphen we cannot use Integer)
account Integer
, Exercise 2.2.1g
Another equivalent way to present the Account relation:
acctNo balance type
34567 25 savings
23456 1000 checking
12345 12000 savings
Another equivalent way to present the Customers relation:
idNo firstName lastName account
805-333 Lena Hand 23456
805-333 Lena Hand 12345
901-222 Robbie Banks 12345
Exercise 2.2.2
Examples of attributes that are created for primarily serving as keys in a relation:
